"sou<TAB>" completes to `sourcekit-lsp` instead of `source`

[certik]

~$ so
sort            sourcekit-lsp   softwareupdate
~$ sourcekit-lsp

And so<TAB> does not even show "source" as a possible completion.

[wolfv]

#226 sorts the tab completion results

[certik]

This is now fixed by #226, it completes source correctly.