clippy: remove assigning_clones lint suppression

[xtqqczze]

The lint was improved so suppression is unnecessary:

• rust-lang/rust-clippy@233b5f2
• rust-lang/rust-clippy@0dc265f

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/tail/follow-name (fails in this run but passes in the 'main' branch)
Congrats! The gnu test tests/dd/stderr is no longer failing!
Congrats! The gnu test tests/tac/tac-2-nonseekable is no longer failing!
Congrats! The gnu test tests/tail/follow-stdin is no longer failing!

[codspeed-hq]

Merging this PR will improve performance by 4.65%

⚡ 3 improved benchmarks
✅ 279 untouched benchmarks
⏩ 38 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Memory	sort_key_field[500000]	32.8 MB	31.4 MB	+4.65%
⚡	Memory	sort_numeric[500000]	48.7 MB	47.3 MB	+3.07%
⚡	Memory	cp_large_file[16]	118 KB	113.1 KB	+4.35%

---

_{Comparing xtqqczze:assigning_clones (b74c201) with main (2d7a3bf)}

Footnotes

1. 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. ↩