Mulliken.py, removed redundant functionalities for plot data, added f…

[AkashHiregange]

…urther documentation and comments to describe the functionality to make life easier. Removed the deprecated matplotlib funcitonality Axes from graphs.py

• Added further documentation and comments to the mulliken.py file
• Removed redundant functionality and changed a few variable names to make life easier
• Removed the deprecated matplotlib import Axes from graph.py and added the latest import line. (This was necessary for the tests to pass)
• All the tests for mulliken analyse works

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 88.35%. Comparing base (77a6af0) to head (8277f97).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #155 +/- ## ========================================== - Coverage 88.44% 88.35% -0.09% ========================================== Files 82 82 Lines 3340 3316 -24 ========================================== - Hits 2954 2930 -24 Misses 386 386 ``` | [Flag](https://app.codecov.io/gh/logsdail/carmm/pull/155/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Andrew+Logsdail) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/logsdail/carmm/pull/155/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Andrew+Logsdail) | `88.35% <100.00%> (-0.09%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Andrew+Logsdail#carryforward-flags-in-the-pull-request-comment) to find out more.

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[logsdail]

@AkashHiregange Is request suitable to be updated, merged and closed? Just clearing out some old bits and hence spotted.

[AkashHiregange]

@AkashHiregange Is request suitable to be updated, merged and closed? Just clearing out some old bits and hence spotted.

Yeah, suitable for merge. The only changes are documentation and removal of some redundancies. Also, the tests were successful on example files.