Add remove() and isRemoved in HTMLRewriterTypes.Doctype interface

[Devanand-Sharma]

What does this PR do?

Resolves #16020

This adds remove() method and removed property to the DOCTYPE handler in HTMLRewriter. These APIs were added in lol-html v0.3.3 but were not accessible through Bun's HTMLRewriter bindings.

• Documentation or TypeScript types
• Code changes

How did you verify your code works?

For Zig files changed:

• I checked the lifetime of memory allocated to verify it's (1) freed and (2) only freed when it should be
• I included a test for the new code: test/js/web/html/html-rewriter-doctype.test.ts
• JSValue used outside outside of the stack is either wrapped in a JSC.Strong or is JSValueProtect'ed
• I wrote TypeScript/JavaScript tests and they pass locally
• I added TypeScript types for the new methods and getter

[Jarred-Sumner]

Looks great. Thank you