Core/Chat: Fix valid chat links being handled as invalid

Fix a case where valid chat links would have been handled as invalid.
This happened if these conditions were true:
- the link was a profession and the link name started with the same name of the profession, like spell id 61120 in esES locale "Inscripción de la tormenta de maestro" with profession name "Inscripción"
- the profession name was the same for more than 1 locale available, like esES and esMX, or enUS and enGB

Restore memmove() instead of memcpy() wrongly replaced in 791130f6fa , it's unsafe to use memcpy() with overlapping memory regions.

src/server/game/Chat/ChatLink.cpp

@@ -314,7 +314,8 @@ bool SpellChatLink::ValidateName(char* buffer, const char* context)
                 // found the prefix, remove it to perform spellname validation below
                 // -2 = strlen(": ")
                 uint32 spellNameLength = strlen(buffer) - skillLineNameLength - 2;
-                memcpy(buffer, buffer + skillLineNameLength + 2, spellNameLength + 1);
+                memmove(buffer, buffer + skillLineNameLength + 2, spellNameLength + 1);
+                break;
             }
         }
     }