engine: a romaji typo stays in the reading

A key that could not go on with the pending romaji, when that was not a
syllable either, committed the whole reading to the application and
passed the key on: one slip dumped かんj into the text with no way back.
The letters typed now stay in the reading as they are, like any other
IME shows them, and Backspace mends them; only a key that starts no
syllable at all still ends the composition.

strans.c

@@ -327,20 +327,21 @@ transjp(Im *p, Rune c)
 		}
 		return e;
 	}
-	if(e.raw.n != 0 && mapget(p->l->map, &e.raw, &mapped)){
-		sappend(&e.next, &mapped);
-		sclear(&e.raw);
-		sclear(&key);
-		sputr(&key, c);
-		if(mapmatch(p->l->map, &key, &mapped) != TrieMiss){
-			e.raw = key;
-			return e;
-		}
+	/* The pending romaji is done: kana if it is complete, else the
+	 * letters as typed, for Backspace to mend. */
+	if(!mapget(p->l->map, &e.raw, &mapped))
+		mapped = e.raw;
+	sappend(&e.next, &mapped);
+	sclear(&e.raw);
+	sclear(&key);
+	sputr(&key, c);
+	if(mapmatch(p->l->map, &key, &mapped) != TrieMiss){
+		e.raw = key;
+		return e;
 	}
 	/* The key starts no syllable: flush the reading and pass it on. */
-	jpreading(p->l->map, &e.next, &e.raw, &e.s);
+	e.s = e.next;
 	sclear(&e.next);
-	sclear(&e.raw);
 	e.eat = 0;
 	return e;
 }