fix: string.match and string.gmatch may return string|number|nil

changelog.md

@@ -4,6 +4,7 @@
 <!-- Add all new changes here. They will be moved under a version at release -->
 * `FIX` Correct `math.type` meta return annotation to use `nil` instead of the string literal `'nil'`
 * `FIX` Fix initial `nameStyle.config` not getting loaded in the appropriate workspace.
+* `FIX` string.match and string.gmatch may return `string|integer?` [#3357](https://github.com/LuaLS/lua-language-server/issues/3357)
 
 ## 3.18.2
 * `CHG` `duplicate-set-field` diagnostic now supports linked suppression: when any occurrence of a duplicate field is suppressed with `---@diagnostic disable` or `---@diagnostic disable-next-line`, all warnings for that field name will be suppressed

meta/template/string.lua

@@ -55,14 +55,14 @@ function string.format(s, ...) end
 ---#if VERSION <= 5.3 then
 ---@param s       string|number
 ---@param pattern string|number
----@return fun():string, ...
+---@return fun():string|integer?, ...
 ---@nodiscard
 function string.gmatch(s, pattern) end
 ---#else
 ---@param s       string|number
 ---@param pattern string|number
 ---@param init?   integer
----@return fun():string, ...
+---@return fun():string|integer?, ...
 function string.gmatch(s, pattern, init) end
 ---#end
 
@@ -91,7 +91,7 @@ function string.lower(s) end
 ---@param s       string|number
 ---@param pattern string|number
 ---@param init?   integer
----@return any ...
+---@return string|integer? ...
 ---@nodiscard
 function string.match(s, pattern, init) end