compress Z extension is removed

[flux242]

with the commit 1c9dfd7#diff-1e41905d9f35a0e2aa259dc7735cf497
the .Z extension was removed for some reason. The standard 'compress' utility adds by default .Z extension. Why was it removed?

[rpdelaney]

Not sure, could be user error.

The single-character extensions tend to be over-detemined though.