Update Go module path from github.com/kovetskiy/mark to
github.com/kovetskiy/mark/v16 across all packages and imports,
following Go module versioning conventions for major versions >= 2.
Also update README installation instructions and version string.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Remove the dead second 'if err != nil' block after the already-checked
lib.Templates assignment.
Add html.EscapeString as 'xmlesc' template function and apply it to
user-controlled string parameters in ac:code, ac:status, and ac:box
templates. Values like .Title, .Color, .Language, and .Theme can contain
XML special characters (<, >, &, ") when supplied by users, which would
break Confluence storage format XML structure.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
