String concatenation used as the argument to StringBuffer.append(),
StringBuilder.append() or Appendable.append().
Such calls may profitably be turned into chained append calls on the existing StringBuffer/Builder/Appendable
saving the cost of an extra StringBuffer/Builder allocation.
This inspection ignores compile-time evaluated String concatenations, in which case the conversion would only
worsen performance.
Example:
void bar(StringBuilder builder, String name) {
builder.append("Hello," + name); //warning
builder.append("Hello," + "world"); //no warning
}