engine: an emoji query shows as typed and Space picks

The emoji search folded the keys for its lookup and then showed and
committed the folded copy: SMILE became smile in the text.  And it
showed the transliteration only while that alone matched, so a Korean
query flipped between 웃 and key soup as it grew.  Now the query shown
is the keys while they match anything, else what they type in the
current language, both as typed; only the lookups fold.  Space in a
search picks the highlighted result as Enter does, instead of adding a
space no alias needs.

README.md

@@ -33,7 +33,7 @@ Japanese consumes the confirming key; Korean and Vietnamese pass it on to
 the application. `Space` adds the reading in Katakana as the last
 candidate, so a word the dictionary lacks converts to Katakana with one
 `Space`. `Backspace` and `Esc` on a chosen candidate go back to the
-reading. In a temporary Emoji or Hanja search, `Enter` commits the
+reading. In a temporary Emoji or Hanja search, `Enter` or `Space` commits the
 highlighted result and `Tab`/`Shift-Tab` wrap through the results. Leaving
 the field or clicking elsewhere commits what is pending. `Esc` cancels a
 Japanese reading or a search; in Korean and Vietnamese it commits the