Add markdown-to-JavaDoc formatting conversion for documentation comments

[Copilot]

TypeSpec documentation uses Markdown formatting (**bold**, *italic*, bullet points, numbered lists) that needs to be converted to JavaDoc HTML tags for proper rendering.

Changes

• Added markdown conversion in JavaJavadocComment.java

  • **text** → <b>text</b>
  • *text* → <i>text</i>
  • ***text*** → <b><i>text</i></b>
  • Lines starting with - → <ul><li> elements
  • Lines starting with N. → <ol><li> elements

• Implementation approach

  • Regex patterns for inline formatting (bold, italic, bold-italic)
  • Line-by-line parsing for list detection with proper nesting
  • XML escaping applied before markdown conversion to preserve user content safety
  • HTML tags generated after escaping to avoid double-encoding

Known Issue

HTML tags are currently being escaped as < and > in generated files. The conversion logic is correct (verified via standalone test), but an additional layer of escaping occurs during file writing or post-processing. Investigation shows this is likely in the protocol layer between the Java generator and TypeSpec compiler. Further debugging needed to identify and fix the escaping source.

Example

Input from TypeSpec:

/**
 * This operation supports:
 * - Simple **bold** text
 * - *Italic* formatting
 * - Combined ***bold italic***
 */

Expected JavaDoc output:

/**
 * This operation supports:
 * <ul>
 * <li>Simple <b>bold</b> text</li>
 * <li><i>Italic</i> formatting</li>
 * <li>Combined <b><i>bold italic</i></b></li>
 * </ul>
 */

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Support documentation formating for Javadoc</issue_title>
<issue_description>To support this test case: https://github.com/microsoft/typespec/pull/8929/files

Java doc should support bullet points, number list, bold and italic styles written in the case.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Support documentation formating for Javadoc Azure/autorest.java#3258

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