Fix sort order alpha (documentationjs#542)

The old code didn't work correctly with regards to making the sort
aware of memberof.

Author: arv

lib/sort.js

@@ -75,8 +75,23 @@ module.exports = function sortDocs(comments, options) {
   return fixed.concat(unfixed);
 };
 
+function compare(a, b) {
+  return a.localeCompare(b, undefined, {caseFirst: 'upper'});
+}
+
 function compareCommentsByName(a, b) {
-  return a.name.localeCompare(b.name, undefined, {caseFirst: 'upper'});
+  var rv;
+  if (a.memberof) {
+    if (b.memberof) {
+      rv = compare(a.memberof, b.memberof);
+    } else {
+      rv = compare(a.memberof, b.name);
+    }
+  } else if (b.memberof) {
+    rv = compare(a.name, b.memberof);
+  }
+
+  return rv || compare(a.name, b.name);
 }
 
 function compareCommentsBySourceLocation(a, b) {

test/fixture/sort-order-alpha.input.js

@@ -7,25 +7,25 @@ function b() {}
 function a() {}
 
 /** */
-class A {
+class C {
   /** */
-  y() {}
+  b() {}
   /** */
-  Y() {}
+  B() {}
   /** */
-  x() {}
+  a() {}
   /** */
-  X() {}
+  A() {}
 }
 
 /** */
-class B {
+class D {
   /** */
-  y() {}
+  b() {}
   /** */
-  Y() {}
+  B() {}
   /** */
-  x() {}
+  a() {}
   /** */
-  X() {}
+  A() {}
 }