Escapes markdown special characters in markdown text blocks. Markdown code blocks follow
different rules and MarkdownInlineCode or MarkdownCodeBlock should be used in that case.
Implements Display to format markdown inline code (wrapped in backticks), handling code that
contains backticks and spaces. All whitespace is treated as a single space character. For text
that does not contain whitespace other than ’ ’, this escaping roundtrips through
pulldown-cmark.