Add atom index to Group()._repr_png_

[hwpang]

Description of Changes

Add atom index consistent with adjacency list to molecule group graph for users' convenience.

[mliu49]

Out of curiosity, what happened with the other PR?

[hwpang]

Out of curiosity, what happened with the other PR?

I was trying to use the PR function in VScode but things didn't work the way I expected lol
Sorry for confusion.

[mliu49]

There is a unit test for the Group.draw method which you will need to update.

[hwpang]

There is a unit test for the Group.draw method which you will need to update.

unit test expected result modified

[codecov]

Codecov Report

Merging #1758 into master will not change coverage.
The diff coverage is 0%.

@@           Coverage Diff           @@
##           master    #1758   +/-   ##
=======================================
  Coverage   32.61%   32.61%           
=======================================
  Files          87       87           
  Lines       26124    26124           
  Branches     6878     6878           
=======================================
  Hits         8521     8521           
+ Misses      16644    16633   -11     
- Partials      959      970   +11

Impacted Files	Coverage Δ
rmgpy/molecule/group.py	0% <0%> (ø)	⬆️
rmgpy/data/statmech.py	42.2% <0%> (ø)	⬆️
rmgpy/rmg/pdep.py	12.21% <0%> (ø)	⬆️
rmgpy/reaction.py	0% <0%> (ø)	⬆️
rmgpy/data/kinetics/family.py	48.35% <0%> (ø)	⬆️
rmgpy/yml.py	15.71% <0%> (ø)	⬆️
rmgpy/data/kinetics/database.py	50.61% <0%> (ø)	⬆️
rmgpy/rmg/input.py	34% <0%> (ø)	⬆️
rmgpy/molecule/molecule.py	0% <0%> (ø)	⬆️
rmgpy/statmech/ndTorsions.py	59.78% <0%> (ø)	⬆️

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[mliu49]

Could you rebase?

[hwpang]

Could you rebase?

Rebase is finished. @mliu49 :-)

[mliu49]

Sorry, I forgot to merge this. Could you rebase again?

[hwpang]

Sorry, I forgot to merge this. Could you rebase again?

I rebased again. Thanks.