gh-122989: Replace duplicate “self.policy.linesep” with “linesep” (#123002)

`linesep` is already defined as `self.policy.linesep`.  It appears that previous refactor was not completed.

diff --git a/Lib/email/generator.py b/Lib/email/generator.py
index 42c84aa4da10444ae1b66c70ece61db6adbcf923..205caf0fe9e81dbdbc96ab873650881734fbfc2c 100644 (file)
--- a/Lib/email/generator.py
+++ b/Lib/email/generator.py
@@ -227,7 +227,7 @@ class Generator:
             folded = self.policy.fold(h, v)
             if self.policy.verify_generated_headers:
                 linesep = self.policy.linesep
-                if not folded.endswith(self.policy.linesep):
+                if not folded.endswith(linesep):
                     raise HeaderWriteError(
                         f'folded header does not end with {linesep!r}: {folded!r}')
                 if NEWLINE_WITHOUT_FWSP.search(folded.removesuffix(linesep)):