Fix typo in signal.c error messages (#437)

613e154 fixed it in one function but not the other two :)

Author: RReverser

libc-bottom-half/signal/signal.c

@@ -30,13 +30,13 @@ static void core_handler(int sig) {
 
 _Noreturn
 static void terminate_handler(int sig) {
-    fprintf(stderr, "Program recieved termination signal: %s\n", strsignal(sig));
+    fprintf(stderr, "Program received termination signal: %s\n", strsignal(sig));
     abort();
 }
 
 _Noreturn
 static void stop_handler(int sig) {
-    fprintf(stderr, "Program recieved stop signal: %s\n", strsignal(sig));
+    fprintf(stderr, "Program received stop signal: %s\n", strsignal(sig));
     abort();
 }