removed signals, deprecated in 1.54.0 and removal announced in 1.68.0 for 1.69.0

Author: jeking3

.gitmodules

@@ -146,10 +146,6 @@
 	path = libs/multi_array
 	url = ../multi_array.git
 	fetchRecurseSubmodules = on-demand
-[submodule "signals"]
-	path = libs/signals
-	url = ../signals.git
-	fetchRecurseSubmodules = on-demand
 [submodule "preprocessor"]
 	path = libs/preprocessor
 	url = ../preprocessor.git