fix(types): add missing @return annotations

runtime/doc/diagnostic.txt

@@ -783,8 +783,9 @@ count({bufnr}, {opts})                                *vim.diagnostic.count()*
       • {opts}   (`vim.diagnostic.GetOpts?`) See |vim.diagnostic.GetOpts|.
 
     Return: ~
-        (`table`) Table with actually present severity values as keys (see
-        |diagnostic-severity|) and integer counts as values.
+        (`table<integer, integer>`) Table with actually present severity
+        values as keys (see |diagnostic-severity|) and integer counts as
+        values.
 
 enable({enable}, {filter})                           *vim.diagnostic.enable()*
     Enables or disables diagnostics.

runtime/doc/lsp.txt

@@ -1637,7 +1637,7 @@ Lua module: vim.lsp.client                                        *lsp-client*
                                 See |Client:exec_cmd()|.
       • {on_attach}             (`fun(self: vim.lsp.Client, bufnr: integer)`)
                                 See |Client:on_attach()|.
-      • {supports_method}       (`fun(self: vim.lsp.Client, method: string|string, bufnr: integer?)`)
+      • {supports_method}       (`fun(self: vim.lsp.Client, method: string|string, bufnr: integer?): boolean`)
                                 See |Client:supports_method()|.
 
 *vim.lsp.Client.Progress*
@@ -1897,6 +1897,9 @@ Client:supports_method({method}, {bufnr})           *Client:supports_method()*
       • {method}  (`string|string`)
       • {bufnr}   (`integer?`)
 
+    Return: ~
+        (`boolean`)
+
 
 ==============================================================================
 Lua module: vim.lsp.codelens                                    *lsp-codelens*

runtime/lua/vim/diagnostic.lua

@@ -1485,7 +1485,7 @@ end
 ---@param bufnr? integer Buffer number to get diagnostics from. Use 0 for
 ---                      current buffer or nil for all buffers.
 ---@param opts? vim.diagnostic.GetOpts
----@return table : Table with actually present severity values as keys
+---@return table<integer, integer> : Table with actually present severity values as keys
 ---                (see |diagnostic-severity|) and integer counts as values.
 function M.count(bufnr, opts)
   vim.validate('bufnr', bufnr, 'number', true)

runtime/lua/vim/lsp/client.lua

@@ -1191,6 +1191,7 @@ end
 --- Note: Some language server capabilities can be file specific.
 --- @param method vim.lsp.protocol.Method.ClientToServer | vim.lsp.protocol.Method.Registration
 --- @param bufnr? integer
+--- @return boolean
 function Client:supports_method(method, bufnr)
   -- Deprecated form
   if type(bufnr) == 'table' then