[LuaDoc] Fix failure to detect that the string type's metatable was overridden

This isn't a generic solution, but at least makes all our built-in stringx methods work.

utils/emmylua/stringx.lua

@@ -3,14 +3,13 @@
 ---@class stringx : stringlib
 stringx = {}
 
-string = stringx
-
 ---Split a string into an array
 ---@param str string
 ---@param sep? string
 ---@param options? {remove_empty:boolean, strip_spaces:boolean, escape:string, quote:string, quote_left:string, quote_right:string, expand_anim:boolean}
 ---@return string[]
 function stringx.split(str, sep, options) end
+string.split = stringx.split
 
 ---Split a string into a maps
 ---@param str string
@@ -19,6 +18,7 @@ function stringx.split(str, sep, options) end
 ---@param options? {remove_empty:boolean, strip_spaces:boolean, default: string}
 ---@return table<string, string>
 function stringx.map_split(str, item_sep, kv_sep, options) end
+string.map_split = stringx.map_split
 
 ---Join a list of strings into a single string
 ---@param strings string[]
@@ -26,6 +26,7 @@ function stringx.map_split(str, item_sep, kv_sep, options) end
 ---@return string
 ---@overload fun(sep:string, strings:string[]):string
 function stringx.join(strings, sep) end
+string.join = stringx.join
 
 ---Join a string map into a ssingle string
 ---@param string_map table<string,string>
@@ -34,30 +35,43 @@ function stringx.join(strings, sep) end
 ---@return string
 ---@overload fun(item_sep:string, string_map:table<string,string>, kv_sep:string):string
 function stringx.join_map(string_map, item_sep, kv_sep) end
+string.join_map = stringx.join_map
 
 ---Substitute variables into a format string
 ---@param format string|tstring
 ---@param values table<string, string|tstring>
 ---@return string|tstring
 function stringx.vformat(format, values) end
+string.vformat = stringx.vformat
 
 ---Formats a list using natural language in the form "a, b, and c"
 ---@param empty tstring
 ---@param strings tstring[]
 function stringx.format_conjunct_list(empty, strings) end
+string.format_conjunct_list = stringx.format_conjunct_list
 
 ---Formats a list using natural language in the form "a, b, or c"
 ---@param empty tstring
 ---@param strings tstring[]
 function stringx.format_disjunct_list(empty, strings) end
+string.format_disjunct_list = stringx.format_disjunct_list
 
 ---Trims leading and trailing whitespace from a string
 ---@param str string
 ---@return string
 function stringx.trim(str) end
+string.trim = stringx.trim
 
 ---Parses a range of the form "1-5" into endpoints
 ---@param range string
 ---@return integer start
 ---@return integer end
 function stringx.parse_range(range) return 0,0 end
+string.parse_range = stringx.parse_range
+
+-- These are defined in lua/core/stringx.lua
+string.escaped_split = stringx.escaped_split
+string.quoted_split = stringx.quoted_split
+string.anim_split = stringx.anim_split
+string.iter_range = stringx.iter_range
+string.iter_ranges = stringx.iter_ranges