Fix misc typos in comments.

Spotted mostly by Fabien Coelho.

Discussion: https://www.postgresql.org/message-id/alpine.DEB.2.21.1901230947050.16643@lancre

Author: hlinnaka

contrib/pgcrypto/pgp-decrypt.c

@@ -132,7 +132,7 @@ pgp_parse_pkt_hdr(PullFilter *src, uint8 *tag, int *len_p, int allow_ctx)
 	int			res;
 	uint8	   *p;
 
-	/* EOF is normal here, thus we dont use GETBYTE */
+	/* EOF is normal here, thus we don't use GETBYTE */
 	res = pullf_read(src, 1, &p);
 	if (res < 0)
 		return res;

src/include/port.h

@@ -471,7 +471,7 @@ extern pqsigfunc pqsignal_no_restart(int signo, pqsigfunc func);
 /* port/quotes.c */
 extern char *escape_single_quotes_ascii(const char *src);
 
-/* port/wait_error.c */
+/* common/wait_error.c */
 extern char *wait_result_to_str(int exit_status);
 
 #endif   /* PG_PORT_H */

src/pl/plpython/plpy_elog.c

@@ -242,7 +242,7 @@ PLy_traceback(PyObject *e, PyObject *v, PyObject *tb,
 
 	*tb_depth = 0;
 	initStringInfo(&tbstr);
-	/* Mimick Python traceback reporting as close as possible. */
+	/* Mimic Python traceback reporting as close as possible. */
 	appendStringInfoString(&tbstr, "Traceback (most recent call last):");
 	while (tb != NULL && tb != Py_None)
 	{