Updated more constants, so that they aren't exported

regex/postfixNode.go

@@ -23,12 +23,12 @@ const (
 )
 
 // Helper constants for lookarounds
-const POSITIVE = 1
-const NEGATIVE = -1
-const LOOKAHEAD = 1
-const LOOKBEHIND = -1
+const positive = 1
+const negative = -1
+const lookahead = 1
+const lookbehind = -1
 
-var INFINITE_REPS int = -1 // Represents infinite reps eg. the end range in {5,}
+var infinite_reps int = -1 // Represents infinite reps eg. the end range in {5,}
 // This represents a node in the postfix representation of the expression
 type postfixNode struct {
 	nodetype       NodeType