Context: MicrosoftDocs/xamarin-docs@fa13cf9

After synchronizing xamarin/xamarin-android docs with
MicrosoftDocs/xamarin-docs, now we synchronize the other way, to
preserve documentation edits.

Note that many of the changes here are to "appease" [Acrolinx][0],
"rewording" the documentation to achieve an Acrolinx score of 80.
Of note:

  * "additional" is not liked.
  * "which" should always follow a comma; use "that" instead.
  * "this" is always potentially ambiguous, and a less ambiguous
    phrase should be used instead.
  * *Informal* writing is preferred (?!), along with greater use of
    contractions.
  * The phrase "Defaults to" is bad.

[0]: https://www.acrolinx.com/