Remove unneeded occurrences of my name in UPGRADING

In NEWS, each 'news item' is suffixed with the name of the developer
who implemented the change. When adding entries to UPGRADING, I used
the same format as NEWS, without thinking about it much. However, it
has come to my attention that the standard format for entries in
UPGRADING does not include the developer's name.

Author: alexdowad

UPGRADING

@@ -101,14 +101,12 @@ PHP 8.3 UPGRADE NOTES
   . mb_strtolower, mb_strtotitle, and mb_convert_case implement conditional
     casing rules for the Greek letter sigma. For mb_convert_case, conditional
     casing only applies to MB_CASE_LOWER and MB_CASE_TITLE modes, not to
-    MB_CASE_LOWER_SIMPLE and MB_CASE_TITLE_SIMPLE. (Alex Dowad)
+    MB_CASE_LOWER_SIMPLE and MB_CASE_TITLE_SIMPLE.
   . mb_decode_mimeheader interprets underscores in QPrint-encoded MIME
     encoded words as required by RFC 2047; they are converted to spaces.
     Underscores must be encoded as "=5F" in such MIME encoded words.
-    (Alex Dowad)
   . In rare cases, mb_encode_mimeheader will transfer-encode its input
     string where it would pass it through as raw ASCII in PHP 8.2.
-    (Alex Dowad)
 
 - mysqli:
   . mysqli_fetch_object now raises a ValueError instead of an Exception when the constructor_args