libyang MAINTENANCE cleanup header includes

Use iwyu tool and fix which headers are included
diff --git a/src/parser_json.c b/src/parser_json.c
index f811b74..24f6544 100644
--- a/src/parser_json.c
+++ b/src/parser_json.c
@@ -25,8 +25,8 @@
 #include "in_internal.h"
 #include "json.h"
 #include "log.h"
+#include "parser_data.h"
 #include "parser_internal.h"
-#include "plugins_exts.h"
 #include "set.h"
 #include "tree.h"
 #include "tree_data.h"