Add missing return values in plugins

plugins/playercommands/rename.sp

@@ -113,6 +113,8 @@ public int MenuHandler_Rename(Menu menu, MenuAction action, int param1, int para
 		}		
 		DisplayRenameTargetMenu(param1);
 	}
+
+	return 0;
 }
 
 void RandomizeName(int client)

plugins/playercommands/slap.sp

@@ -112,6 +112,8 @@ public int MenuHandler_SlapDamage(Menu menu, MenuAction action, int param1, int
 		
 		DisplaySlapTargetMenu(param1);
 	}
+
+	return 0;
 }
 
 public int MenuHandler_Slap(Menu menu, MenuAction action, int param1, int param2)
@@ -157,6 +159,8 @@ public int MenuHandler_Slap(Menu menu, MenuAction action, int param1, int param2
 		
 		DisplaySlapTargetMenu(param1);
 	}
+
+	return 0;
 }
 
 public Action Command_Slap(int client, int args)

plugins/playercommands/slay.sp

@@ -111,6 +111,8 @@ public int MenuHandler_Slay(Menu menu, MenuAction action, int param1, int param2
 		
 		DisplaySlayMenu(param1);
 	}
+
+	return 0;
 }
 
 public Action Command_Slay(int client, int args)