pr: ignore empty line after newline char

[jfinkels]

Depends on #10303.

Fix a bug in pr where a form feed character (\f) immediately
following a newline character (\n) was incorrectly rendered as an
extra blank line in the output when running with the -f option. After
this commit, the empty line is correctly ignored.

[codspeed-hq]

CodSpeed Performance Report

Merging this PR will degrade performance by 3.67%

_{Comparing jfinkels:pr-newline-form-feed (0e36e4b) with main (2122c52)¹}

Summary

❌ 2 regressed benchmarks
✅ 280 untouched benchmarks
⏩ 38 skipped benchmarks²

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Memory	du_wide_tree[(5000, 500)]	1.2 MB	1.3 MB	-3.67%
❌	Memory	dd_copy_partial	129.1 KB	133.5 KB	-3.26%

Footnotes

1. No successful run was found on main (1a81d1b) during the generation of this report, so 2122c52 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

2. 38 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/tail/follow-name (fails in this run but passes in the 'main' branch)