__init__(): The docstring was incorrect regarding how header wrapping

gets done when maxheaderlen <> 0.  The header really gets wrapped via
the email.Header.Header class, which has a more sophisticated
algorithm than just splitting on semi-colons.

Lib/email/Generator.py

@@ -70,11 +70,10 @@ class Generator:
 
         Optional maxheaderlen specifies the longest length for a non-continued
         header.  When a header line is longer (in characters, with tabs
-        expanded to 8 spaces), than maxheaderlen, the header will be broken on
-        semicolons and continued as per RFC 2822.  If no semicolon is found,
-        then the header is left alone.  Set to zero to disable wrapping
-        headers.  Default is 78, as recommended (but not required by RFC
-        2822.
+        expanded to 8 spaces) than maxheaderlen, the header will split as
+        defined in the Header class.  Set maxheaderlen to zero to disable
+        header wrapping.  The default is 78, as recommended (but not required)
+        by RFC 2822.
         """
         self._fp = outfp
         self._mangle_from_ = mangle_from_