Core/Spells:

* Implemented on CheckCast spell script hook
* Added possibility to send SPELL_FAILED_CUSTOM_ERROR and added enum with all possible options for it

Scripts/Spells:
* Added example script for CheckCast hook with SPELL_FAILED_CUSTOM_ERROR (profession research and Book of Glyph Mastery)

src/server/game/Skills/SkillDiscovery.h

@@ -25,6 +25,7 @@ class Player;
 
 void LoadSkillDiscoveryTable();
 uint32 GetSkillDiscoverySpell(uint32 skillId, uint32 spellId, Player* player);
+bool HasDiscoveredAllSpells(uint32 spellId, Player* player);
 uint32 GetExplicitDiscoverySpell(uint32 spellId, Player* player);
 #endif