docs: correct parenthesis placement in 'man/tmpfiles.d.xml'

Correct the parenthesis placement in 'man/tmpfiles.d.xml' to prevent the
following formatting:

> lock ( shared or exclusive) is

man/tmpfiles.d.xml

@@ -678,8 +678,8 @@ d /tmp/foo/bar - - - bmA:1h -</programlisting></para>
 
       <para>Note that while the aging algorithm is run an exclusive BSD file lock (see <citerefentry
       project='man-pages'><refentrytitle>flock</refentrytitle><manvolnum>2</manvolnum></citerefentry>) is
-      taken on each directory/file the algorithm decides to remove. If the aging algorithm finds a lock (
-      shared or exclusive) is already taken on some directory/file, it (and everything below it) is skipped.
+      taken on each directory/file the algorithm decides to remove. If the aging algorithm finds a lock
+      (shared or exclusive) is already taken on some directory/file, it (and everything below it) is skipped.
       Applications may use this to temporarily exclude certain directory subtrees from the aging algorithm:
       the applications can take a BSD file lock themselves, and as long as they keep it aging of the
       directory/file and everything below it is disabled.</para>