data(emoji): every emoji, with its CLDR names in English, Korean, and Japanese

emoji.src was a seed of thirty emoji.  cldr2emoji now generates it from
Unicode's emoji-test.txt (Emoji 17.0) and CLDR 48.2.0's annotations: the
1914 fully-qualified emoji without their skin-tone variants, each with
its names and keywords in the three languages, so that a search finds
what fcitx5's emoji picker finds.  The data is under the Unicode License,
added to LICENSES.

README.md

@@ -37,7 +37,10 @@ syllable and goes on to the application, so it still leaves insert mode.
 Hiragana mode composes a complete reading before offering Kanji candidates.
 Katakana mode does not perform Kanji conversion. Emoji and Hanja searches
 return to the previous mode after use; switching language during a search
-commits the shown query. `Ctrl+H` takes the syllable being composed as its
+commits the shown query. The Emoji search matches the typed keys, and what
+they spell in the current language, against a prefix of every emoji's
+CLDR name and keywords in English, Korean, and Japanese, and against ASCII
+symbol aliases such as `->` and `<=`. `Ctrl+H` takes the syllable being composed as its
 query; the Hanja dictionary lists one modern Hangul syllable at a time.
 
 ## Preedit and candidates