doc: updated links

TODO

@@ -26,3 +26,4 @@ Next:
  - the Perfect Model.
  - page size 0 -> page less mode
  - test meta_associative_container::meta_iterator::value fro non-key-only, const value
+ - add ::reach and rev iterators to views and groups for raw, faster and unsafe iterations

docs/md/links.md

@@ -104,12 +104,11 @@ I hope this list can grow much more in the future:
   * [Creating Minecraft in One Week with C++ and Vulkan](https://vazgriz.com/189/creating-minecraft-in-one-week-with-c-and-vulkan/):
     a crack at recreating Minecraft in one week using a custom C++ engine and
     Vulkan ([code included](https://github.com/vazgriz/VoxelGame)).
-  * [Intro to EnTT](https://www.youtube.com/watch?v=D4hz0wEB978&feature=youtu.be):
-    [Game Engine series](https://www.youtube.com/c/TheChernoProject/videos) by
-    [The Cherno](https://github.com/TheCherno).
-  * [Entities and Components](https://www.youtube.com/watch?v=-B1iu4QJTUc&feature=youtu.be):
-    [Game Engine series](https://www.youtube.com/c/TheChernoProject/videos) by
-    [The Cherno](https://github.com/TheCherno).
+  * [Game Engine series](https://www.youtube.com/c/TheChernoProject/videos) by
+    [The Cherno](https://github.com/TheCherno):
+    - [Intro to EnTT](https://www.youtube.com/watch?v=D4hz0wEB978&feature=youtu.be).
+    - [Entities and Components](https://www.youtube.com/watch?v=-B1iu4QJTUc&feature=youtu.be).
+    - [The ENTITY Class](https://www.youtube.com/watch?v=GfSzeAcsBb0).
   * [Ability Creator](https://www.erichildebrand.net/blog/ability-creator-project-retrospect):
     project retrospect by [Eric Hildebrand](https://www.erichildebrand.net/).