Function escape_md_cell 

pub fn escape_md_cell(s: &str) -> Cow<'_, str>

Escape a string for safe inclusion inside a GFM table cell.

Per the GFM spec, an unescaped | inside a cell ends the cell — every subsequent character on the line lands in the next column, so a single stray pipe in a path / author name / commit message silently corrupts the entire row’s column alignment. The escape is a leading backslash on the pipe character.

Newlines and carriage returns inside a cell are GFM-unsupported entirely (the table row terminates at the line break), so they get replaced with the visual ↵ glyph to preserve the cell boundary rather than break the row.

Returns Cow::Borrowed for the common case (no escape needed) so the happy path is allocation-free. The borrow checker thread-of- life this preserves matters here — every analysis emits hundreds to thousands of rows and the markdown emitter is a hot path for the $GITHUB_STEP_SUMMARY flow.