Fix half-qwerty layout and keyd's path in doc

[Zwyx]

Hi!

Thank you so much for having made Keyd! I was using an XKB configuration which was not perfectly supported by every application. I recreated my layout using keyd, and it's now flawless.

I am so impressed by the level of quality you have put into keyd. Your way of managing hybrid modifiers is so clever (if I understand correctly, you send a fake control press to prevent a press of a modifier (for instance Alt) from having an effect (for instance focusing the menu bar of the current application)). Very clever.

Keyd offers many customisation possibilities, while having a configuration format easy to understand. Such a breath of fresh air after XKB!

Anyway, here's a small PR of various things I picked up along the way.

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Fix Half-Qwerty layout Enter key

return was used instead of enter.

Fix keyd path in doc

From /usr/share/keyd to /usr/local/share/keyd, which is confirmed by PREFIX in the makefile.

Fix various minor typos

[rvaiya]

This will be /usr/share on most distros, /usr/local/ is conventionally used for packages installed from source. Other than that the PR looks good :).

[rvaiya]

Thanks :). A lot of thought went into the design of modifier layers to make sure they didn't break existing modifier semantics (which most other tools don't seem to care about).

The PR looks good, but I would appreciate if you could squash it into a single commit and make the minor change mentioned above.

[Zwyx]

No worries of course! I've reverted the addition of /local in the path (I'm surprised because the Makefile does contain it, but I'm definitely no expert), and I've squashed all the commits together 👍