Core/SpellScripts: rename GetTarget*() functions to GetExplTarget*(), so the names reflect better what those functions do. Also update some comments.

src/server/scripts/Spells/spell_dk.cpp

@@ -775,7 +775,7 @@ class spell_dk_death_grip : public SpellScriptLoader
             void HandleDummy(SpellEffIndex /*effIndex*/)
             {
                 int32 damage = GetEffectValue();
-                Position const* pos = GetTargetDest();
+                Position const* pos = GetExplTargetDest();
                 if (Unit* target = GetHitUnit())
                 {
                     if (!target->HasAuraType(SPELL_AURA_DEFLECT_SPELLS)) // Deterrence