Docs: Give documentation examples better names

These names come from the bookmaker generated md files.

Also, delete ducplicated and empty examples.

A later CL will re-name the cpp files.

Change-Id: Ie365b9cc1cc705d010c674b9988b32c8307a0455
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/201609
Commit-Queue: Hal Canary <halcanary@google.com>
Reviewed-by: Hal Canary <halcanary@google.com>
diff --git a/docs/examples/IRect_041.cpp b/docs/examples/IRect_041.cpp
index 901d569..896c817 100644
--- a/docs/examples/IRect_041.cpp
+++ b/docs/examples/IRect_041.cpp
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
 #include "fiddle/examples.h"
 // HASH=d35fbc9fdea71df8b8a12fd3da50d11c
-REG_FIDDLE(IRect_041, 256, 256, true, 0) {
+REG_FIDDLE(IRect_intersectNoEmptyCheck, 256, 256, true, 0) {
 void draw(SkCanvas* canvas) {
     SkIRect result;
     if (result.intersectNoEmptyCheck({ 10, 40, 50, 80 }, { 30, 60, 70, 90 })) {