In an effort to make angular documentation easier for users to read,
we are moving the router tutorial currently in router.md to a new file.
To support this change, we have done the following:
* Update files to fix any broken links caused by moving the file
* Updated the new file to follow tutorial guidelines
* Add the new file to the table of contents under, Tutorials.
PR Close#37979
Krzysztof Platis
Olegas Goncarovas
David Shevitz 🔵