Add missing new-line at the end of lint.ignore

[jiangzhaoming]

This PR add a missing new line at the end of lint.ignore, to fix the broken CTS CI workflow which would write line to that file assuming there is a new line existed at the end of file.

[jiangzhaoming]

@past @Ms2ger @titzer @jgraham Please take a look, thanks!
This issue is imported via PR #49809, which modifies the lint.ignore but miss the new line at the end of file.

[jiangzhaoming]

@greggman @Jiawei-Shao @shaoboyan091 I think this is the cause of WebGPU CTS CI workflow failure, and I test this fix could fix it.

The workflow (example) has a step of echo "TRAILING WHITESPACE, INDENT TABS, CR AT EOL: *.bin" >> wpt/lint.ignore right before running ./wpt lint, namely adding wpt lint ignore rule for *.bin, and the missing new line make the modified file ends with

PROMISE_REJECTS: wasm/core/js/harness/testharness.jsTRAILING WHITESPACE, INDENT TABS, CR AT EOL: *.bin

instead of

PROMISE_REJECTS: wasm/core/js/harness/testharness.js
TRAILING WHITESPACE, INDENT TABS, CR AT EOL: *.bin

and fails the parser.

[jiangzhaoming]

Thanks for reviewing!