plot voltage components has correct legend order

[dion-w]

Description

Fixed the order of legend entries in plot_voltage_components.py. Now every color matches the legend entry. Before Voltage referred to the OCV, OCV to reaction overpotential, etc.

Type of change

Please add a line in the relevant section of CHANGELOG.md to document the change (include PR #) - note reverse order of PR #s. If necessary, also add to the list of breaking changes.

• Optimization (back-end change that speeds up the code)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)

Key checklist:

• No style issues: $ flake8
• All tests pass: $ python run-tests.py --unit
• The documentation builds: $ cd docs and then $ make clean; make html

You can run all three at once, using $ python run-tests.py --quick.

Further checks:

• Code is commented, particularly in hard-to-understand areas
• Tests added that prove fix is effective or that feature works

[codecov]

Codecov Report

Merging #2061 (b6ce3df) into develop (7fd5155) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #2061      +/-   ##
===========================================
- Coverage    99.36%   99.35%   -0.01%     
===========================================
  Files          346      346              
  Lines        19033    19033              
===========================================
- Hits         18912    18911       -1     
- Misses         121      122       +1     

Impacted Files	Coverage Δ
pybamm/plotting/plot_voltage_components.py	100.00% <ø> (ø)
pybamm/expression_tree/symbol.py	98.53% <0.00%> (-0.25%)	⬇️

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[valentinsulzer]

Thanks!

[valentinsulzer]

Actually the order is now wrong for me, and correct if I change it back ... maybe it behaves differently on different computers??

[valentinsulzer]

We should just use label= to be safe