engine: a search just begun shows itself

Ctrl+E and Ctrl+H gave no sign until a key produced candidates; with
nothing pending the popup even went away.  An empty search now shows
☺ or 漢 in the popup, so the user knows the next keys are a query.

README.md

@@ -43,7 +43,8 @@ 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; `Esc` in a Hanja search gives the syllable back
-to the composition. The Emoji search matches the typed keys, and what
+to the composition. A search with nothing typed yet shows ☺ or 漢 in the
+popup. 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

strans.c

@@ -192,6 +192,8 @@ snapshot(Drawcmd *dc)
 		impre(&im, &pre);
 	if(!(activecap & Cclientpreedit))
 		dc->pre = pre;
+	if(search.lang && pre.n == 0)	/* a search just begun shows itself */
+		sputr(&dc->pre, search.lang == LangEMOJI ? L'☺' : L'漢');
 	first = pagefirst();
 	n = im.nkouho - first;
 	if(n > Maxdisp) n = Maxdisp;

tests/engine_test.c

@@ -1359,6 +1359,8 @@ engine_emoji_single_candidate(struct ct *t)
 	CT_CHECK(t, keystroke('e', Mctrl, &com));
 	CT_CHECK(t, search.lang);
 	CT_EQ_INT(t, LangKO, im.l->lang);
+	if(CT_CHECK(t, draindraw(&dc) > 0))
+		checkstr(t, "empty search shows itself", "☺", &dc.pre);
 	if(typekeys(t, "alpha", &com)){
 		checkstr(t, "no automatic commit", "", &com);
 		checkstr(t, "raw English query", "alpha", &search.text);