feat(evil): shorten evil-window-* prefix in which-key

[wchmb]

Mirrors the treatment given to evilem-motion-* in ea6fa50, stripping the redundant `evil-window-' prefix from which-key's popup under the C-w window prefix.

Fix: #29
Amend: ea6fa50

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• I searched the issue tracker and this hasn't been PRed before.
• My changes are not on the do-not-PR list for this project.
• My commits conform to Doom's git conventions.
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• This PR contains AI-generated work.
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• This a draft PR; I need more time to finish it.

[hlissner]

Spurred on by recent changes (doomemacs/core@de2a3364a, c8f828c08) to which-key integration, truncation of these long commands have been standardized behind a doom-which-key-trim-prefixes variable, and I've added "^evil-" to it in c8f828c08, which I think adequately shortens these commands' labels, I thought "window" was important enough not to cut out, which is why I didn't add a "^evil-window-" as well. In any case, I'll consider this resolved. Thanks for bringing it to my attention!