Add trailing commas to enum definitions

Since C99, there can be a trailing comma after the last value in an
enum definition.  A lot of new code has been introducing this style on
the fly.  Some new patches are now taking an inconsistent approach to
this.  Some add the last comma on the fly if they add a new last
value, some are trying to preserve the existing style in each place,
some are even dropping the last comma if there was one.  We could
nudge this all in a consistent direction if we just add the trailing
commas everywhere once.

I omitted a few places where there was a fixed "last" value that will
always stay last.  I also skipped the header files of libpq and ecpg,
in case people want to use those with older compilers.  There were
also a small number of cases where the enum type wasn't used anywhere
(but the enum values were), which ended up confusing pgindent a bit,
so I left those alone.

Discussion: https://www.postgresql.org/message-id/flat/386f8c45-c8ac-4681-8add-e3b0852c1620%40eisentraut.org

src/bin/pgbench/pgbench.c

@@ -227,7 +227,7 @@ typedef enum
 {
 	PART_NONE,					/* no partitioning */
 	PART_RANGE,					/* range partitioning */
-	PART_HASH					/* hash partitioning */
+	PART_HASH,					/* hash partitioning */
 } partition_method_t;
 
 static partition_method_t partition_method = PART_NONE;
@@ -459,7 +459,7 @@ typedef enum EStatus
 	/* SQL errors */
 	ESTATUS_SERIALIZATION_ERROR,
 	ESTATUS_DEADLOCK_ERROR,
-	ESTATUS_OTHER_SQL_ERROR
+	ESTATUS_OTHER_SQL_ERROR,
 } EStatus;
 
 /*
@@ -470,7 +470,7 @@ typedef enum TStatus
 	TSTATUS_IDLE,
 	TSTATUS_IN_BLOCK,
 	TSTATUS_CONN_ERROR,
-	TSTATUS_OTHER_ERROR
+	TSTATUS_OTHER_ERROR,
 } TStatus;
 
 /* Various random sequences are initialized from this one. */
@@ -587,7 +587,7 @@ typedef enum
 	 * aborted because a command failed, CSTATE_FINISHED means success.
 	 */
 	CSTATE_ABORTED,
-	CSTATE_FINISHED
+	CSTATE_FINISHED,
 } ConnectionStateEnum;
 
 /*
@@ -697,7 +697,7 @@ typedef enum MetaCommand
 	META_ELSE,					/* \else */
 	META_ENDIF,					/* \endif */
 	META_STARTPIPELINE,			/* \startpipeline */
-	META_ENDPIPELINE			/* \endpipeline */
+	META_ENDPIPELINE,			/* \endpipeline */
 } MetaCommand;
 
 typedef enum QueryMode