Rename "positive electrode diffusivity" to "positive particle diffusivity"?

[valentinsulzer]

It's a better name, but a breaking change so maybe not worth it.
We can make it not breaking by returning "positive particle diffusivity" from parameter_values["Positive electrode diffusivity"] with a deprecation warning

[brosaplanella]

Non-breaking change with deprecation warning sounds good to me.

[rtimms]

Agreed.

[ejfdickinson]

"Positive electrode particle diffusivity" feels more correct albeit more verbose. What's a 'positive particle'..?

[valentinsulzer]

I think "positive particle" is fairly self-explanatory, we already have a bunch of variables like "Positive particle concentration"