fixing some :class:, :meth: roles

[fchapoton]

📚 Description

This just fixes two wrong uses of the class and meth roles in the doc,

📝 Checklist

• I have made sure that the title is self-explanatory and the description concisely explains the PR.
• I have linked an issue or discussion.
• I have created tests covering the changes.
• I have updated the documentation accordingly.

⌛ Dependencies

[github-actions]

Documentation preview for this PR is ready! 🎉
Built with commit: 68fde19

[codecov-commenter]

Codecov Report

Patch coverage: 100.00% and no project coverage change

Comparison is base (52a81cb) 88.57% compared to head (68fde19) 88.57%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop   #35224   +/-   ##
========================================
  Coverage    88.57%   88.57%           
========================================
  Files         2140     2140           
  Lines       397273   397273           
========================================
+ Hits        351891   351901   +10     
+ Misses       45382    45372   -10     

Impacted Files	Coverage Δ
src/sage/combinat/integer_vector.py	93.42% <ø> (ø)
src/sage/modular/modform/element.py	90.86% <100.00%> (ø)
...e/combinat/cluster_algebra_quiver/mutation_type.py	48.21% <0.00%> (-3.92%)	⬇️
src/sage/graphs/generators/random.py	91.26% <0.00%> (-1.20%)	⬇️
src/sage/groups/generic.py	88.34% <0.00%> (-0.68%)	⬇️
src/sage/modular/modform/numerical.py	94.19% <0.00%> (-0.65%)	⬇️
...sage/geometry/hyperbolic_space/hyperbolic_model.py	88.95% <0.00%> (-0.62%)	⬇️
src/sage/categories/weyl_groups.py	96.47% <0.00%> (-0.59%)	⬇️
src/sage/rings/algebraic_closure_finite_field.py	94.24% <0.00%> (-0.45%)	⬇️
src/sage/cpython/_py2_random.py	76.03% <0.00%> (-0.42%)	⬇️
... and 24 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[roed314]

The failed test is independent of this PR (though I'll note that the long time tag is placed on the wrong line there: it's supposed to be on the first line of a multi-line doctest).

sage: all(L.change_ring(SR).is_cross_positive_on(K)
    for L in K.cross_positive_operators_gens())  # long time ## line 17206 ##