Fix word bounds on filters, where they would only be applied at the beginning (#61714)

code/controllers/configuration/configuration.dm

@@ -430,7 +430,7 @@ Example config:
 			to_join_on_whitespace_splits += REGEX_QUOTE(banned_word)
 
 	var/whitespace_split = @"(?:(?:^|\s+)(" + jointext(to_join_on_whitespace_splits, "|") + @")(?:$|\s+))"
-	var/word_bounds = @"(\b(" + jointext(to_join_on_word_bounds, "|") + "))"
+	var/word_bounds = @"(\b(" + jointext(to_join_on_word_bounds, "|") + @")\b)"
 	return regex("([whitespace_split]|[word_bounds])", "i")
 
 //Message admins when you can.

code/modules/unit_tests/chat_filter.dm

@@ -20,6 +20,14 @@
 		null,
 	)
 
+	test_filter(
+		"these words have filtered words in them: ablockedinic blockedinicbbbb aablockedinicbb",
+		null,
+		null,
+		null,
+		null,
+	)
+
 	test_filter(
 		"<(0_0<) <(0_0)> (>0_0)> KIRBY DANCE!!!",
 		"<(0_0<)",