Examples for xAOD

[gordonwatts]

• Example that uses the internal xAOD typing that is done by default in the xAOD backend (there isn't much!).
• Simple example that uses the typed interface to access jets.
• Added changes to examples.rst to reference these examples.

Fixes #454

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.28%. Comparing base (989c7bb) to head (802caaa).

Additional details and impacted files

@@            Coverage Diff            @@
##           doc_week     #455   +/-   ##
=========================================
  Coverage     82.28%   82.28%           
=========================================
  Files            26       26           
  Lines          1383     1383           
=========================================
  Hits           1138     1138           
  Misses          245      245           

Flag	Coverage Δ
unittests	82.28% <ø> (ø)

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[BenGalewsky]

These are great examples! Please add these to examples.rst

I updated the PR to merge into doc_week branch since that is where the latest docs are

[gordonwatts]

Thanks, @BenGalewsky !!! I'll do that now! I just came here to rebase. :-)