Indent C code in flex and bison files

In the style of pgindent, done semi-manually.

Discussion: https://www.postgresql.org/message-id/flat/7d062ecc-7444-23ec-a159-acd8adf9b586%40enterprisedb.com

contrib/seg/segparse.y

@@ -38,8 +38,10 @@ static char strbuf[25] = {
 %expect 0
 %name-prefix="seg_yy"
 
-%union {
-	struct BND {
+%union
+{
+	struct BND
+	{
 		float		val;
 		char		ext;
 		char		sigd;

src/backend/bootstrap/bootparse.y

@@ -401,6 +401,7 @@ boot_index_param:
 		boot_ident boot_ident
 				{
 					IndexElem  *n = makeNode(IndexElem);
+
 					n->name = $1;
 					n->expr = NULL;
 					n->indexcolname = NULL;

src/backend/replication/repl_gram.y

@@ -42,11 +42,11 @@ Node *replication_parse_result;
 %expect 0
 %name-prefix="replication_yy"
 
-%union {
+%union
+{
 	char	   *str;
 	bool		boolval;
 	uint32		uintval;
-
 	XLogRecPtr	recptr;
 	Node	   *node;
 	List	   *list;

src/backend/replication/repl_scanner.l

@@ -170,6 +170,7 @@ WAIT				{ return K_WAIT; }
 
 <xd>{xdstop}	{
 					int			len;
+
 					yyless(1);
 					BEGIN(INITIAL);
 					yylval.str = litbufdup();

src/backend/utils/adt/jsonpath_gram.y

@@ -77,7 +77,8 @@ static JsonPathParseItem *makeItemLikeRegex(JsonPathParseItem *expr,
 %error-verbose
 %parse-param {JsonPathParseResult **result}
 
-%union {
+%union
+{
 	JsonPathString		str;
 	List			   *elems;	/* list of JsonPathParseItem */
 	List			   *indexs;	/* list of integers */

src/pl/plpgsql/src/pl_gram.y

@@ -116,7 +116,8 @@ static	void			check_raise_parameters(PLpgSQL_stmt_raise *stmt);
 %name-prefix="plpgsql_yy"
 %locations
 
-%union {
+%union
+{
 	core_YYSTYPE core_yystype;
 	/* these fields must match core_YYSTYPE: */
 	int			ival;