private ExecutableElement getter(String name) {
      Preconditions.checkArgument(names().contains(name), "Getter by name %s not found in %s", name, type.name());
      return getters.get(name);
    }
Get attribute name from java bean getter. Some examples:
<pre>
  getA -> a
  getAB -> AB (fist 2 chars are uppercase)
  getABC -> ABC (fist 2 chars are uppercase)
  getAb -> ab
  getAbc -> abc
  getFoo -> foo
</pre>

<p>See 8.8 Capitalization of inferred names in
<a href="https://download.oracle.com/otndocs/jcp/7224-javabeans-1.01-fr-spec-oth-JSpec/">javabean spec</a>
value-processor/src/org/immutables/value/processor/meta/JavaBeanAttributesCollector.java