devel/xxhash: Fix manpage symbolic links

• Bump PORTREVISION for package change

Before:
lrwx------ 1 sunpoet wheel 15 Jun 22 21:30 xxh128sum.1.gz@ -> cli/xxhsum.1.gz
lrwx------ 1 sunpoet wheel 15 Jun 22 21:30 xxh32sum.1.gz@ -> cli/xxhsum.1.gz
lrwx------ 1 sunpoet wheel 15 Jun 22 21:30 xxh64sum.1.gz@ -> cli/xxhsum.1.gz
-rw-r--r-- 1 sunpoet wheel 1887 Jun 22 21:30 xxhsum.1.gz

After:
lrwx------ 1 sunpoet wheel 11 Jun 22 21:31 xxh64sum.1.gz -> xxhsum.1.gz
lrwx------ 1 sunpoet wheel 11 Jun 22 21:31 xxh32sum.1.gz -> xxhsum.1.gz
lrwx------ 1 sunpoet wheel 11 Jun 22 21:31 xxh128sum.1.gz -> xxhsum.1.gz
-rw-r--r-- 1 sunpoet wheel 1887 Jun 22 21:31 xxhsum.1.gz

PR: 264821
Reported by: Ivan Rozhuk <rozhuk.im@gmail.com>