perf(line): render line without clone

[EdJoPaTo]

Due to the truncation the non truncation path used to_owned which cloned the line.

Calling an inner function on both cases resolves this as the temporary truncated line lives long enough for that function to end.

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I have not benchmarked this. This is part of the improvements I did with #1049.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 94.1%. Comparing base (366c2a0) to head (7623df8).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1082 +/- ## ======================================= + Coverage 89.4% 94.1% +4.7% ======================================= Files 61 61 Lines 15440 14632 -808 ======================================= - Hits 13808 13777 -31 + Misses 1632 855 -777 ```

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[EdJoPaTo]

Superseded by #1089