SyntaxStringBuilder appendIf() method

[erenkarakal]

Problem

The addition of SyntaxStringBuilder was to make toString() methods easier to write and read, but when you have to do

SyntaxStringBuilder ssb = new SyntaxStringBuilder(event, debug)
if (condition) {
  ssb.append("a");
}

It's not any different, if not worse than just using normal strings.

Solution

This PR solves this issue by adding an appendIf() method. The new code would look like:

return new SyntaxStringBuilder(event, debug)
    .append("push", entities)
    .appendIf(direction != null, direction)
    .toString()

Testing Completed

Supporting Information

---

Completes: none
Related: none