Fix "found unknown escape character" while trying to run swiftlint 0.18.1

Also update the smiley face regex check to have a space before the colon so that it doesn't match: fatalError("init(coder:) has not been implemented")

Author: jawwad

.swiftlint.yml

@@ -17,8 +17,8 @@ disabled_rules:
 custom_rules:
   smiley_face:
     name: "Smiley Face"
-    regex: "(\:\))"
-    match_kinds: 
+    regex: '( :\))'
+    match_kinds:
       - comment
       - string
     message: "A closing parenthesis smiley :) creates a half-hearted smile, and thus is not preferred. Use :]"