Rollup merge of #94178 - est31:tolerant_lines_check, r=Mark-Simulacrum

tidy: fire less "ignoring file length unneccessarily" warnings

This avoids a situation where a file is at the border of the limit,
and alternates between hitting the limit and not hitting it, causing
a back and forth of addition of the ignore-tidy-linelength directive.

As an example, consider the ignore-tidy-filelength of compiler/rustc_typeck/src/collect.rs.

It was added in 2ca4964db5, removed in
37354ebc97 (a revert of the earlier commit), added again in 448d07683a,
removed in 3171bd5bf5, added in 438826fd1a,
and removed in bb0a2f985c.

To avoid this back and forth, we exempt files from the unneccessary
ignoring warning that have length of at least 70% of the limit.

src/tools/tidy/src/style.rs

@@ -395,6 +395,9 @@ pub fn check(path: &Path, bad: &mut bool) {
                 );
             };
             suppressible_tidy_err!(err, skip_file_length, "");
+        } else if lines > (LINES * 7) / 10 {
+            // Just set it to something that doesn't trigger the "unneccessarily ignored" warning.
+            skip_file_length = Directive::Ignore(true);
         }
 
         if let Directive::Ignore(false) = skip_cr {