doc: Add docs for uri functions (#12887)

runtime/lua/vim/uri.lua

@@ -7,6 +7,9 @@
 local uri_decode
 do
   local schar = string.char
+
+  --- Convert hex to char
+  --@private
   local function hex_to_char(hex)
     return schar(tonumber(hex, 16))
   end
@@ -34,6 +37,8 @@ do
   else
     tohex = function(b) return string.format("%02x", b) end
   end
+
+  --@private
   local function percent_encode_char(char)
     return "%"..tohex(sbyte(char), 2)
   end
@@ -45,10 +50,14 @@ do
 end
 
 
+--@private
 local function is_windows_file_uri(uri)
   return uri:match('^file:///[a-zA-Z]:') ~= nil
 end
 
+--- Get a URI from a file path.
+--@param path (string): Path to file
+--@return URI
 local function uri_from_fname(path)
   local volume_path, fname = path:match("^([a-zA-Z]:)(.*)")
   local is_windows = volume_path ~= nil
@@ -67,6 +76,9 @@ end
 
 local URI_SCHEME_PATTERN = '^([a-zA-Z]+[a-zA-Z0-9+-.]*)://.*'
 
+--- Get a URI from a bufnr
+--@param bufnr (number): Buffer number
+--@return URI
 local function uri_from_bufnr(bufnr)
   local fname = vim.api.nvim_buf_get_name(bufnr)
   local scheme = fname:match(URI_SCHEME_PATTERN)
@@ -77,6 +89,9 @@ local function uri_from_bufnr(bufnr)
   end
 end
 
+--- Get a filename from a URI
+--@param uri (string): The URI
+--@return Filename
 local function uri_to_fname(uri)
   local scheme = assert(uri:match(URI_SCHEME_PATTERN), 'URI must contain a scheme: ' .. uri)
   if scheme ~= 'file' then
@@ -93,7 +108,10 @@ local function uri_to_fname(uri)
   return uri
 end
 
--- Return or create a buffer for a uri.
+--- Return or create a buffer for a uri.
+--@param uri (string): The URI
+--@return bufnr.
+--@note Creates buffer but does not load it
 local function uri_to_bufnr(uri)
   local scheme = assert(uri:match(URI_SCHEME_PATTERN), 'URI must contain a scheme: ' .. uri)
   if scheme == 'file' then