Use 'CONCAT' instead of literally specifiying the rune

misc.go

@@ -17,7 +17,7 @@ var NONCAPLPAREN_CHAR rune = 0xF0006 // Represents a non-capturing group's LPARE
 var ESC_BACKSLASH rune = 0xF0007     // Represents an escaped backslash
 var CHAR_RANGE rune = 0xF0008        // Represents a character range
 
-var specialChars = []rune{'?', '*', '\\', '^', '$', '{', '}', '(', ')', '[', ']', '+', '|', '.', '~', '<', '>', LBRACKET, RBRACKET, NONCAPLPAREN_CHAR}
+var specialChars = []rune{'?', '*', '\\', '^', '$', '{', '}', '(', ')', '[', ']', '+', '|', '.', CONCAT, '<', '>', LBRACKET, RBRACKET, NONCAPLPAREN_CHAR}
 
 // An interface for int and rune, which are identical
 type character interface {