rules: fix check for appending '|' character when applying

rules: fix check for appending '|' character when applying

There are two ways to separate multiple files in XKB include statements:
'+' will cause the later file to override the first in case of conflict,
while '|' will cause it augment it (this is done by xkbcomp). '!' is
unrelated here.
Since '|' is practically never used, this wasn't noticed.

In the modified test, the '|some_compat' previously was just ignored.

Signed-off-by: Ran Benita <ran234@gmail.com>