Add new feature attribute

[xuhuanzy]

No description provided.

[gemini-code-assist]

Summary of Changes

Hello @xuhuanzy, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly extends the EmmyLua parser by integrating a new attribute feature. This allows for more expressive and structured documentation within Lua code, enabling developers to define custom metadata tags and apply them to code elements. The changes involve updates across the lexer, parser, and syntax definitions to support both the declaration and application of these attributes, complete with argument parsing.

Highlights

• New Attribute Feature: Introduced the attribute feature, allowing users to define custom attributes (---@attribute) and apply them (---@[attribute_name(params)]) within LuaDoc comments.
• Parser Extensions: Added new syntax kinds and parsing logic to emmylua_parser to correctly interpret attribute definitions and their usage, including attribute names and argument lists.
• Lexer Updates: Enhanced the LuaDoc lexer with new token kinds and a dedicated state (AttributeUsage) to accurately tokenize the new attribute syntax.
• Test Coverage: Included a new test case to ensure the proper parsing and Abstract Syntax Tree (AST) generation for the attribute feature.

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[gemini-code-assist]

Code Review

This pull request introduces a new attribute feature, allowing for attribute definitions with ---@attribute and their usage with ---@[...]. The implementation spans across the lexer, parser, and syntax kinds, and includes a new test case.

The changes are well-structured. I've found one area in the attribute argument list parsing where the code can be simplified by removing redundant whitespace handling and clarifying the loop logic.

[gemini-code-assist]

The logic for parsing the attribute argument list can be simplified.

1. The LuaDocParser is already configured to skip whitespace tokens when the lexer is in the AttributeUsage state. Therefore, the manual while p.current_token() == LuaTokenKind::TkWhitespace loops are redundant.
2. The main while loop can be refactored into a more idiomatic loop for parsing comma-separated lists, which improves readability and explicitly handles trailing commas.

Here is a suggested simplification:

    if p.current_token() != LuaTokenKind::TkRightParen {
        loop {
            if p.current_token() == LuaTokenKind::TkEof {
                break;
            }
            parse_attribute_arg(p)?;
            if p.current_token() != LuaTokenKind::TkComma {
                break;
            }
            p.bump(); // consume comma
            if p.current_token() == LuaTokenKind::TkRightParen {
                break; // trailing comma
            }
        }
    }