tests/test-custom-filters.out

commands: more informative description of "!" files in status

This makes the description more similar to the one used by Subversion.
Suggestion by Dennis Brakhane.

% Repository data:
Some stuff to ponder very carefully.
% Fresh checkout:
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
Copyright 2046, The Masters
Some stuff to ponder very carefully.
M stuff.txt
% Problem encoding:
abort: missing header "Copyright 2046, The Masters" in morestuff.txt
M stuff.txt
A morestuff.txt