plugin api: export scnotification_get_type

Updated scintilla_changes.patch accordingly

scintilla/gtk/ScintillaGTK.cxx

@@ -3250,6 +3250,7 @@ void scintilla_release_resources(void) {
 static void *copy_(void *src) { return src; }
 static void free_(void *doc) { }
 
+GEANY_API_SYMBOL
 GType scnotification_get_type(void) {
 	static gsize type_id = 0;
 	if (g_once_init_enter(&type_id)) {

scintilla/scintilla_changes.patch

@@ -50,6 +50,14 @@ index 0871ca2..49dc278 100644
  GtkWidget *scintilla_object_new() {
  	return scintilla_new();
  }
+@@ -3250,6 +3250,7 @@ void scintilla_release_resources(void) {
+ static void *copy_(void *src) { return src; }
+ static void free_(void *doc) { }
+ 
++GEANY_API_SYMBOL
+ GType scnotification_get_type(void) {
+ 	static gsize type_id = 0;
+ 	if (g_once_init_enter(&type_id)) {
 diff --git scintilla/src/Catalogue.cxx scintilla/src/Catalogue.cxx
 index ed47aa8..e58f1ab 100644
 --- scintilla/src/Catalogue.cxx