Add missing spaces after single-line comments

Only 1 of 3 of these changes appear to be handled by pgindent. That change
is new to v15.  The remaining two appear to be left alone by pgindent. The
exact reason for that is not 100% clear to me.  It seems related to the
fact that it's a line that contains *only* a single line comment and no
actual code.  It does not seem worth investigating this in too much
detail.  In any case, these do not conform to our usual practices, so fix
them.

Author: Justin Pryzby
Discussion: https://postgr.es/m/20220411020336.GB26620@telsasoft.com

src/backend/storage/file/fd.c

@@ -912,7 +912,7 @@ InitFileAccess(void)
 void
 InitTemporaryFileAccess(void)
 {
-	Assert(SizeVfdCache != 0);	/* InitFileAccess() needs to have run*/
+	Assert(SizeVfdCache != 0);	/* InitFileAccess() needs to have run */
 	Assert(!temporary_files_allowed);	/* call me only once */
 
 	/*

src/include/replication/message.h

@@ -32,7 +32,7 @@ typedef struct xl_logical_message
 extern XLogRecPtr LogLogicalMessage(const char *prefix, const char *message,
 									size_t size, bool transactional);
 
-/* RMGR API*/
+/* RMGR API */
 #define XLOG_LOGICAL_MESSAGE	0x00
 void		logicalmsg_redo(XLogReaderState *record);
 void		logicalmsg_desc(StringInfo buf, XLogReaderState *record);

src/include/tsearch/ts_type.h

@@ -171,7 +171,7 @@ typedef struct
 
 extern PGDLLIMPORT const int tsearch_op_priority[OP_COUNT];
 
-/* get operation priority  by its code*/
+/* get operation priority by its code */
 #define OP_PRIORITY(x)	( tsearch_op_priority[(x) - 1] )
 /* get QueryOperator priority */
 #define QO_PRIORITY(x)	OP_PRIORITY(((QueryOperator *) (x))->oper)