Support \$ as literal $ in replaceMatches substitution string

Author: cmoesel

examples/browser/cql4browsers.js

@@ -7237,7 +7237,7 @@ class ReplaceMatches extends expression_1.Expression {
             return null;
         }
         else {
-            return args[0].replace(new RegExp(args[1], 'g'), args[2]);
+            return args[0].replace(new RegExp(args[1], 'g'), args[2].replace(/\\\$/g, '$$'));
         }
     }
 }

src/elm/string.ts

@@ -246,7 +246,7 @@ export class ReplaceMatches extends Expression {
     if (args.some((x: any) => x == null)) {
       return null;
     } else {
-      return args[0].replace(new RegExp(args[1], 'g'), args[2]);
+      return args[0].replace(new RegExp(args[1], 'g'), args[2].replace(/\\\$/g, '$$'));
     }
   }
 }