StrSubstitutor: Ability to turn off substitution in values

StrSubstitutor replaces variables in values. And currently there's no way to turn this off.

Why turn it off: I want to replace some variables in a simple template. Some of the replacement values are arbitrary user input.

At the moment I escape all dollar signs in the replacement values with "$$". This is annoying. Especially as I use one template with variables as a value for another variable. Here I have to escape twice.

Here's some example code. At the moment it prints:

Hello Hamburg from Hamburg

The commented line is my suggestion for this feature. If it works, it should print:

Hello ${city} from Hamburg

// untrusted user input
String userInputName = "${city}";
String userInputCity = "Hamburg";

Map<String, String> valueMap = new HashMap<>();
valueMap.put("name", userInputName);
valueMap.put("city", userInputCity);

String source = "Hello ${name} from ${city}";

StrSubstitutor strSubstitutor = new StrSubstitutor(valueMap);
// strSubstitutor.setEnableSubstitutionInValues(false);
System.out.println(strSubstitutor.replace(source));