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

changelog.md

@@ -3,6 +3,7 @@
 ## Unreleased
 <!-- Add all new changes here. They will be moved under a version at release -->
 * `CHG` Modified the `ResolveRequire` function to pass the source URI as a third argument.
+* `FIX` string.match and string.gmatch may return `string|integer?` [#3357](https://github.com/LuaLS/lua-language-server/issues/3357)
 
 ## 3.17.1
 `2026-01-20`

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