Model Variable Naming Sprint: Part 4

[ss421]

Description

As part of variable name code sprint, this PR renames variables from group 4:

potential_temperature -> air_potential_temperature
exner_levels -> dimensionless_exner_function_levels

I didn't find any instances of:
exner -> dimensionless_exner_function
exner_levels_minus_one -> dimensionless_exner_function_levels_minus_one

Issue(s) addressed

A separate one was not created.

Dependencies

build-group=https://github.com/JCSDA-internal/saber/pull/955
build-group=https://github.com/JCSDA-internal/ufo/pull/3485
build-group=JCSDA-internal/ufo-data#453
build-group=https://github.com/JCSDA-internal/vader/pull/276
build-group=https://github.com/JCSDA-internal/lfric-jedi/pull/908
build-group=https://github.com/JCSDA-internal/ops-um-jedi/pull/235
build-group=https://github.com/MetOffice/jjtests/pull/48

Impact

No impacts expected beyond the list in dependencies above

Checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have run the unit tests before creating the PR

[ctgh]

Thanks for adding this. Did you also want to change exner_levels?

[ss421]

Thanks for adding this. Did you also want to change exner_levels?

@ctgh Thanks! I seem to have totally missed that :-(. I've updated it now and comited at: f999db6

[ctgh]

Thanks, looks good to me!