zless(1): handle uncompressed files

[fernape]

Summary

In the manual page for zmore(1) and zless(1) it is said that zless(1) is
equivalent to zmore(1) except that it uses less(1) as a pager. However
zmore(1) is able to handle uncompressed files transparently while zless(1)
is not.

Add another case to the switch in lesspipe.sh to handle non-compressed files.

PR: 196437
Reported by: [e-mail]

Test Plan

Before the patch:

$ echo "Hello world!" > test
$ gzip test
$ zmore test.gz
Hello world!
$ zless test.gz
<shows file>
$ zmore test
Hello world!
$ zless test








test (END)

After the patch, zless test shows the file normally. This also is in sync with
the manual page.

[mjg]

on linux zless can do it so why not

[fernape]

Thanks for the review!