LatinIME: add Greek dictionary to spell check

[cardaris]

Add the precompiled main_el.dict resource and register “el” in spellchecker.xml so that Greek suggestions are enabled. Expose “Greek” in Keyboard Settings > Add-on dictionaries by adding the corresponding UI string and array entry.

[cardaris]

Hi @thestinger,

I noticed that Greek spell check support was missing entirely from the GrapheneOS keyboard settings. To enable Greek spell-checking, I’ve:

• Added the el entry to spellchecker.xml so that the Greek locale is recognized.
• Included the precompiled main_el.dict file under java/res/raw/.

I’ve prepared PR #35 that includes the precompiled main_el.dict and updates spellchecker.xml to register "el", ensuring Greek suggestions are enabled. Please let me know if any further adjustments are needed. Thanks for your review!