code: public void addReplacementRule(char target, Character replacement, String refinementName) {
      if (!((Character) target).equals(replacement)) {
        replacementRules.add(new UrlReplacementRule(target, replacement, refinementName));
      }
    }
docs: <code>
  Adds a new replacement rule that will only be applied to the specified refinement. The original
  search term and refinements will be put back into the query object.
  If replacement is null the target character will be removed.
  Note: Replacements that are chained may still contain the original target character.
  For example:
  addReplacementRule('x', 'y', "brand");
  addReplacementRule('z', 'x', "brand");
  The result of this may contain x's in the final result.
  www.example.com/xyz/b will become www.example.com/yyz/b after the first replacement and www.example.com/yyx/b
  after the second replacement.
  </code>
  
  @param target
  The char values to be replaced
  @param replacement
  The replacement char value
  @param refinementName
  The name of the refinement that this replacement should be applied to.