rename Open-circuit voltage to Bulk open-circuit voltage

[valentinsulzer]

Description

Renames "Open-circuit voltage" to "Bulk open-circuit voltage" to leave it fully up to the user which OCV to use. See #2740 (comment) and discussion below

Fixes # (issue)

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.

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

Key checklist:

• No style issues: $ pre-commit run (see CONTRIBUTING.md for how to set this up to run automatically when committing locally, in just two lines of code)
• All tests pass: $ python run-tests.py --all
• The documentation builds: $ python run-tests.py --doctest

You can run unit and doctests together 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

Patch and project coverage have no change.

Comparison is base (cc1bff5) 99.69% compared to head (bf594c6) 99.69%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #2845   +/-   ##
========================================
  Coverage    99.69%   99.69%           
========================================
  Files          273      273           
  Lines        19065    19065           
========================================
  Hits         19006    19006           
  Misses          59       59           

Impacted Files	Coverage Δ
...m/models/full_battery_models/base_battery_model.py	99.76% <ø> (ø)
pybamm/util.py	100.00% <ø> (ø)

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.