[📃 Docs]: Fix typos on certain pages of Keep Docs Site

[Rutam21]

In the pages listed below, there are a few typos that need to be fixed. Find the page links and the screenshots attached for reference.

The page files are found inside the /docs folder.

Auth0 Page

Adding a new Provider Page

Key concepts Page

Introduction Page

Examples Page

• [x] I am willing to submit a PR to fix this.

[Rutam21]

@talboren This issue can be closed as well. The PR is merged already.

[Matvey-Kuk]

Thank you @Rutam21 !