* Extend solution explanation
The explanation for the advanced code solution was a little cumbersome.
It tried to explain the used method, but also tried to explain an alternative solution, both mixed together.
To fix that, I moved everything related to the alternative solution to another paragraph.
Additionally, I added a more detailed explanation about this alternative solution.
Hopefully, with this fixes, both solutions will be clearer to the user.
* Replace intermediate solution
Replace the intermediate solution with a more concise one.
I took the opportunity to eliminate the indenting in all 3 snippets to remove unnecessary blank space on the left.
I also changed the wording on one of the instructions and fixed a typo.
* Remove external links
* Simplity regex declaration
I replaced `new RegExp()` in order to make the solution cleaner and shorter
* Update index.md
