Add support for Table of Contents [[TOC]] Rendering in Issue Comments

Summary

Add support for Table of Contents syntax [[_TOC_]] in issue comments to improve navigation and readability of long comments with multiple sections.

Problem

Currently, the [[_TOC_]] syntax is not supported in issue comments and appears as plain text instead of generating an interactive table of contents. This limits the ability to create well-structured, navigable comments for complex discussions or documentation.

Proposal

Enable the [[_TOC_]] syntax to work in issue comments, generating clickable table of contents that link to headings within the same comment.