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

[carsakiller]

Closes #3357 by correcting the definitions for string.gmatch and string.match. They can return an integer if you use index capturing.

Technically, on Lua versions without the integer type, it returns string|number?, but I believe integer is a backwards-compatible "pseudo type" in the language server that is just number|integer with some additional validation magic.

[gemini-code-assist]

Summary of Changes

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This pull request enhances the type definitions for Lua's string.gmatch and string.match functions within the language server's template. The changes ensure that the type annotations accurately reflect the possibility of these functions returning integers, particularly when using index capturing, thereby improving the overall type-checking accuracy and developer experience.

Highlights

• Type Definition Correction: Updated the return type annotations for string.gmatch to correctly include 'integer?' as a possible return value, reflecting its behavior with index capturing.
• Improved Type Accuracy: Refined the return type annotation for string.match from 'any' to 'string|integer?', providing more precise type information for its various return scenarios.

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Changelog

• meta/template/string.lua
  • Corrected the return type for string.gmatch to include integer?
  • Updated the return type for string.match from any to string|integer?

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[gemini-code-assist]

Code Review

This pull request corrects the return type definitions for string.gmatch and string.match in the Lua standard library metadata. The previous definitions were incomplete, as they did not account for position captures which can return numbers (integers), or optional captures that don't match, which can return nil. The changes update the return types to string|integer? ... for string.match and fun():string|integer?, ... for string.gmatch, which accurately reflects that these functions can return strings, integers, or nil values. The changes are correct and improve the accuracy of the type information for the language server.