Improve JS/TS/TSX parameter highlighting for destructuring

[feeiyu]

Objective

Fixes #51967

Destructured JS/TS/TSX parameters with defaults were not highlighted consistently as parameters when using themes that distinguish arguments from variables/properties, such as Catppuccin.

For example, in:

function a({ argument = true }) {}

argument was parsed under a default assignment pattern and did not receive the same @variable.parameter capture as a destructured parameter without a default.

This also affected array binding patterns with defaults, such as:

function b([argument = true]) {}

Solution

Updated the JS/TS/TSX highlight queries to capture destructured parameters with default values as @variable.parameter.

This covers both:

• Object binding patterns with defaults, such as { argument = true }
• Array binding patterns with defaults, such as [argument = true]

As a result, destructured parameters are highlighted consistently whether or not they provide a default value.

Testing

• Verified the highlight query changes for JavaScript/TypeScript destructured parameters with defaults.
• Tested examples include:

  function a({ argument }) {}
  function a({ argument = true }) {}
  function a({ argument = true }?) {} //optional
  function b([argument]) {}
  function b([argument = true]) {}
  function b([argument = true]?) {} // optional

• These cases should be easiest to visually confirm with a theme that distinguishes parameters from variables/properties, such as Catppuccin.

Self-Review Checklist:

• I've reviewed my own diff for quality, security, and reliability
• Unsafe blocks (if any) have justifying comments
• The content adheres to Zed's UI standards (UX/UI and icon guidelines)
• Tests cover the new/changed behavior
• Performance impact has been considered and is acceptable

Showcase

Before this change,

After this change:

Release Notes:

• Fixed inconsistent syntax highlighting for JS/TS/TSX destructured parameters with default values.

[ChristopherBiscardi]

thanks!