fix(lzip): fix broken case patterns for long and short options

The original codes before PR 862,

https://github.com/scop/bash-completion/pull/862/files#diff-87387e55a9536f7ac2aa5fce39d9a0442c29ec2058215563388d5a284a9ac1c1L15-R24

were already broken.  According to the man page of lzip, lzip supports
separate options `--decompress` and `-d`, but there are no options
`--decompress-d` or `--decompress-...d`.  In this patch, we separate
these unexpectedly combined option names.

Reference:

#914 (comment)

Co-authored-by: Ville Skyttä <[email protected]>

Author: akinomyoga

completions/lzip

@@ -14,14 +14,14 @@ _lzip()
             --volume-size | --data-size | -${noargopts}@([bmsSB]|[hV]*))
             return
             ;;
-        --decompress-${noargopts}d)
+        --decompress | -${noargopts}d)
             decompress=true
             ;;
-        --threads-${noargopts}n)
+        --threads | -${noargopts}n)
             COMPREPLY=($(compgen -W "{1..$(_ncpus)}" -- "$cur"))
             return
             ;;
-        --output-${noargopts}o)
+        --output | -${noargopts}o)
             _filedir
             return
             ;;