add ipython extension for rich

[nathanrpage97]

Type of changes

• Bug fix
• New feature
• Documentation / docstrings
• Tests
• Other

Checklist

• I've run the latest black with default args on new code.
• I've updated CHANGELOG.md and CONTRIBUTORS.md where appropriate.
• I've added tests for new code.
• I accept that @willmcgugan may be pedantic in the code review.

Description

I think that we can provide better integration with IPython by creating an extension. For now I have kept it rather basic, but later on there could be custom magic commands that could be added.

[nathanrpage97]

If you do not want it in the __init__.py then we could rename _extension.py to ipython.py and have the user call it via %load_ext rich.ipython. This is a common convention I see being used by the IPython community.

[codecov]

Codecov Report

Merging #1274 (9a65f49) into master (d5d08a2) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1274   +/-   ##
=======================================
  Coverage   99.73%   99.73%           
=======================================
  Files          69       70    +1     
  Lines        6459     6461    +2     
=======================================
+ Hits         6442     6444    +2     
  Misses         17       17           

Flag	Coverage Δ
unittests	99.73% <100.00%> (+<0.01%)	⬆️

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Impacted Files	Coverage Δ
rich/__init__.py	100.00% <100.00%> (ø)
rich/_extension.py	100.00% <100.00%> (ø)

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[willmcgugan]

Thanks!