Documentation for BC's in v2.0

[jhdark]

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.50%. Comparing base (a02ed4b) to head (7aa0ca6).
⚠️ Report is 121 commits behind head on fenicsx.

Additional details and impacted files

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##           fenicsx     #974      +/-   ##
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- Coverage    95.56%   95.50%   -0.07%     
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  Files           45       45              
  Lines         3089     3089              
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- Hits          2952     2950       -2     
- Misses         137      139       +2     

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[RemDelaporteMathurin]

It may be worth stating somewhere that all boundary conditions need to have a SurfaceSudomain object, with a link to the Subdomain section

[RemDelaporteMathurin]

I see this is explained for heat transfer so maybe not needed

[RemDelaporteMathurin]

Here, it is quite important to detail the mathematical description of these reactions. Either here or in the theory section because there is a slight change compared to FESTIM1.

Maybe a first usage example would be the H2 <-> 2H reaction.

Then the A + B <-> AB reaction

Then the full:

A + B <-> AB
A + A <-> A
B + B <-> BB

[RemDelaporteMathurin]

I wonder if we can cover isotopic exchange like

H2O (g) + T (adsorbed) <-> HTO + H (adsorbed)

or

H2 (g) + T (ad) <-> HT (g) + H (ad)

I don't think we can atm

[RemDelaporteMathurin]

Btw, this can cover tri-species reactions too:

ABC <-> A + B + C

[RemDelaporteMathurin]

I'm happy with the changes. I would just spend some time detailing the theory of the surface reactions in the Theory section