feat(lua): show proper verbose output for lua configuration

`:verbose` didn't work properly with lua configs (For example:
    options or keymaps are set from lua, just say that they were set
    from lua, doesn't say where they were set at.

This fixes that issue. Now `:verbose` will provide filename and line no
when option/keymap is set from lua.

Changes:
  - compiles lua/vim/keymap.lua as vim/keymap.lua
 - When souring a lua file current_sctx.sc_sid is set to SID_LUA
 - Moved finding scripts SID out of `do_source()` to `get_current_script_id()`.
   So it can be reused for lua files.
 - Added new function `nlua_get_sctx` that extracts current lua scripts
   name and line no with debug library. And creates a sctx for it.
     NOTE: This function ignores C functions and blacklist which
     currently contains only vim/_meta.lua so vim.o/opt wrappers aren't
     targeted.
 - Added function `nlua_set_sctx` that changes provided sctx to current
   lua scripts sctx if a lua file is being executed.
 - Added tests in tests/functional/lua/verbose_spec.lua
 - add primary support for additional types (:autocmd, :function, :syntax) to lua verbose
    Note: These can't yet be directly set from lua but once that's possible
    :verbose should work for them hopefully :D
 - add :verbose support for nvim_exec & nvim_command within lua
    Currently auto commands/commands/functions ... can only be defined
    by nvim_exec/nvim_command this adds support for them. Means if those
    Are defined within lua with vim.cmd/nvim_exec :verbose will show their
    location . Though note it'll show the line no on which nvim_exec call was made.

src/nvim/api/buffer.c

@@ -953,11 +953,11 @@ ArrayOf(Dictionary) nvim_buf_get_keymap(uint64_t channel_id, Buffer buffer, Stri
 /// @see |nvim_set_keymap()|
 ///
 /// @param  buffer  Buffer handle, or 0 for current buffer
-void nvim_buf_set_keymap(Buffer buffer, String mode, String lhs, String rhs, Dict(keymap) *opts,
-                         Error *err)
+void nvim_buf_set_keymap(uint64_t channel_id, Buffer buffer, String mode, String lhs, String rhs,
+                         Dict(keymap) *opts, Error *err)
   FUNC_API_SINCE(6)
 {
-  modify_keymap(buffer, false, mode, lhs, rhs, opts, err);
+  modify_keymap(channel_id, buffer, false, mode, lhs, rhs, opts, err);
 }
 
 /// Unmaps a buffer-local |mapping| for the given mode.
@@ -965,11 +965,12 @@ void nvim_buf_set_keymap(Buffer buffer, String mode, String lhs, String rhs, Dic
 /// @see |nvim_del_keymap()|
 ///
 /// @param  buffer  Buffer handle, or 0 for current buffer
-void nvim_buf_del_keymap(Buffer buffer, String mode, String lhs, Error *err)
+void nvim_buf_del_keymap(uint64_t channel_id, Buffer buffer, String mode,
+                         String lhs, Error *err)
   FUNC_API_SINCE(6)
 {
   String rhs = { .data = "", .size = 0 };
-  modify_keymap(buffer, true, mode, lhs, rhs, NULL, err);
+  modify_keymap(channel_id, buffer, true, mode, lhs, rhs, NULL, err);
 }
 
 /// Gets a map of buffer-local |user-commands|.

src/nvim/api/deprecated.c

@@ -22,11 +22,11 @@
 
 /// @deprecated
 /// @see nvim_exec
-String nvim_command_output(String command, Error *err)
+String nvim_command_output(uint64_t channel_id, String command, Error *err)
   FUNC_API_SINCE(1)
   FUNC_API_DEPRECATED_SINCE(7)
 {
-  return nvim_exec(command, true, err);
+  return nvim_exec(channel_id, command, true, err);
 }
 
 /// @deprecated Use nvim_exec_lua() instead.

src/nvim/api/private/helpers.c

@@ -585,8 +585,8 @@ Array string_to_array(const String input, bool crlf)
 /// @param  buffer    Buffer handle for a specific buffer, or 0 for the current
 ///                   buffer, or -1 to signify global behavior ("all buffers")
 /// @param  is_unmap  When true, removes the mapping that matches {lhs}.
-void modify_keymap(Buffer buffer, bool is_unmap, String mode, String lhs, String rhs,
-                   Dict(keymap) *opts, Error *err)
+void modify_keymap(uint64_t channel_id, Buffer buffer, bool is_unmap, String mode, String lhs,
+                   String rhs, Dict(keymap) *opts, Error *err)
 {
   LuaRef lua_funcref = LUA_NOREF;
   bool global = (buffer == -1);
@@ -599,6 +599,8 @@ void modify_keymap(Buffer buffer, bool is_unmap, String mode, String lhs, String
     return;
   }
 
+  const sctx_T save_current_sctx = api_set_sctx(channel_id);
+
   if (opts != NULL && opts->callback.type == kObjectTypeLuaRef) {
     lua_funcref = opts->callback.data.luaref;
     opts->callback.data.luaref = LUA_NOREF;
@@ -710,6 +712,7 @@ void modify_keymap(Buffer buffer, bool is_unmap, String mode, String lhs, String
 
   parsed_args.rhs_lua = LUA_NOREF;  // don't clear ref on success
 fail_and_free:
+  current_sctx = save_current_sctx;
   NLUA_CLEAR_REF(parsed_args.rhs_lua);
   xfree(parsed_args.rhs);
   xfree(parsed_args.orig_rhs);
@@ -1622,3 +1625,20 @@ int find_sid(uint64_t channel_id)
     return SID_API_CLIENT;
   }
 }
+
+/// Sets sctx for API calls.
+///
+/// @param channel_id     api clients id. Used to determine if it's a internal
+///                       call or a rpc call.
+/// @return returns       previous value of current_sctx. To be used
+///                       to be used for restoring sctx to previous state.
+sctx_T api_set_sctx(uint64_t channel_id)
+{
+  sctx_T old_current_sctx = current_sctx;
+  if (channel_id != VIML_INTERNAL_CALL) {
+    current_sctx.sc_sid =
+      channel_id == LUA_INTERNAL_CALL ? SID_LUA : SID_API_CLIENT;
+    current_sctx.sc_lnum = 0;
+  }
+  return old_current_sctx;
+}

src/nvim/api/vim.c

@@ -1586,6 +1586,7 @@ ArrayOf(Dictionary) nvim_get_keymap(uint64_t channel_id, String mode)
 ///     nmap <nowait> <Space><NL> <Nop>
 /// </pre>
 ///
+/// @param channel_id
 /// @param  mode  Mode short-name (map command prefix: "n", "i", "v", "x", …)
 ///               or "!" for |:map!|, or empty string for |:map|.
 /// @param  lhs   Left-hand-side |{lhs}| of the mapping.
@@ -1597,10 +1598,11 @@ ArrayOf(Dictionary) nvim_get_keymap(uint64_t channel_id, String mode)
 ///               a Lua function to call when the mapping is executed.
 ///               Values are Booleans. Unknown key is an error.
 /// @param[out]   err   Error details, if any.
-void nvim_set_keymap(String mode, String lhs, String rhs, Dict(keymap) *opts, Error *err)
+void nvim_set_keymap(uint64_t channel_id, String mode, String lhs, String rhs, Dict(keymap) *opts,
+                     Error *err)
   FUNC_API_SINCE(6)
 {
-  modify_keymap(-1, false, mode, lhs, rhs, opts, err);
+  modify_keymap(channel_id, -1, false, mode, lhs, rhs, opts, err);
 }
 
 /// Unmaps a global |mapping| for the given mode.
@@ -1608,10 +1610,10 @@ void nvim_set_keymap(String mode, String lhs, String rhs, Dict(keymap) *opts, Er
 /// To unmap a buffer-local mapping, use |nvim_buf_del_keymap()|.
 ///
 /// @see |nvim_set_keymap()|
-void nvim_del_keymap(String mode, String lhs, Error *err)
+void nvim_del_keymap(uint64_t channel_id, String mode, String lhs, Error *err)
   FUNC_API_SINCE(6)
 {
-  nvim_buf_del_keymap(-1, mode, lhs, err);
+  nvim_buf_del_keymap(channel_id, -1, mode, lhs, err);
 }
 
 /// Gets a map of global (non-buffer-local) Ex commands.

src/nvim/api/vimscript.c

@@ -37,7 +37,7 @@
 /// @param[out] err Error details (Vim error), if any
 /// @return Output (non-error, non-shell |:!|) if `output` is true,
 ///         else empty string.
-String nvim_exec(String src, Boolean output, Error *err)
+String nvim_exec(uint64_t channel_id, String src, Boolean output, Error *err)
   FUNC_API_SINCE(7)
 {
   const int save_msg_silent = msg_silent;
@@ -52,11 +52,16 @@ String nvim_exec(String src, Boolean output, Error *err)
   if (output) {
     msg_silent++;
   }
+
+  const sctx_T save_current_sctx = api_set_sctx(channel_id);
+
   do_source_str(src.data, "nvim_exec()");
   if (output) {
     capture_ga = save_capture_ga;
     msg_silent = save_msg_silent;
   }
+
+  current_sctx = save_current_sctx;
   try_end(err);
 
   if (ERROR_SET(err)) {