Update examples to use new fluxes notation

[glwagner]

This PR updates the examples to use the notation for fluxes which is used by Wagner et al 2024 and which we are planning to use for subsequent work as well. In short this is:

• $Q$ for heat flux
• $\tau_x$ and $\tau_y$ for the zonal and meridional kinematic momentum flux. The momentum flux is therefore $\rho_o \tau_x$, where $\rho_o$ is the ocean surface density. This is also consistent with the notation used for Clima's atmosphere model
• $J^c$ for the flux of a tracer $c$.

[navidcy]

Lgtm

[glwagner]

does anyone ever say "lbtm"

[navidcy]

Haha

You hope that it that’s the case they are more explicit to what doesn’t good that good