Docs / examples fixes.

[anntzer]

examples/axes_grid1/parasite_simple2.py

See #5864 for the weirdness before the fix.

After the fix (master / 1.5.0):

[anntzer]

Bundling in an unrelated broken link fix.

[mdboom]

I think the failure is unrelated (we've seen it creep up in other PRs).

👍 from me otherwise, though.

[zblz]

@anntzer - I fixed the arcsecond thing in #5880, so now $''/yr$ should parse correctly (as in TeX). I'm not sure whether it's worth making the change to \prime if it will get typeset correctly (eventually) as it is now.

[anntzer]

Then I'd still need to change $^{''}$ to $''$ right? A quick check with usetex=True tells me $^{''}$ is even smaller (which makes sense as $'$ is $^\prime$ and \prime is a larger version of ').

[zblz]

Yes! I did not realize the original was $^{''}$, that definitely makes no sense.

[jenshnielsen]

Thanks Backported to 1.5.x as 6405839