Do not forget to increment the input line counter

when reading a word spanning multiple lines.

PR:		bin/101094
MFC after:	5 days

bin/sh/parser.c

@@ -952,6 +952,7 @@ readtoken1(int firstc, char const *syntax, char *eofmark, int striptabs)
 					USTPUTC('\\', out);
 					pungetc();
 				} else if (c == '\n') {
+					plinno++;
 					if (doprompt)
 						setprompt(2);
 					else