The format_header() function was not calling format_inline_content()
to process inline formatting like **bold**, *italic*, and `code`
within headers. This caused raw markdown markers to appear in output.
Added 4 tests to verify the fix:
- test_bold_inside_header
- test_italic_inside_header
- test_code_inside_header
- test_mixed_formatting_inside_header
The code fence (```) was not being properly detected during streaming,
causing it to be rendered as inline code instead of a code block.
Root cause: When buffering a code fence after seeing ```, the code
was returning early for ALL characters including newlines. This meant
handle_newline() was never called and block_state was never set to
BlockState::CodeBlock.
Fixes:
- Don't return early for newlines when buffering code fence, allow them
to fall through to handle_newline()
- Support indented code fences (up to 3 spaces per CommonMark spec) by
using trim_start() when checking for ``` at line start
Bug 1: Inline code after list bullets not detected
- After emitting a list bullet, at_line_start was not set to false
- This caused the next backtick to be treated as a potential code fence
- Fixed by setting at_line_start = false after emitting bullet
Bug 2: Code block closing on indented backticks
- Code blocks containing indented ``` (4+ spaces) were closing prematurely
- The .trim() check was too permissive
- Fixed by only allowing closing fence with <= 3 spaces indent (CommonMark spec)
Added tests for both edge cases.
