The inline-code/fence restore step matched the placeholder index with a
greedy `(\d+)`, so a digit in user text immediately after a code span
(e.g. `code`5) was absorbed into the index, resolved to undefined, and
`?? ""` deleted both the code span and the digit. Terminate the
placeholder index with the existing NUL marker so the index boundary is
unambiguous.
Co-authored-by: Dr Rushindra Sinha <5796457+rushindrasinha@users.noreply.github.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>