Add Numerical and Exact Fields as Category

[mjungmath]

We add exact and numerical fields to the category framework as suggested in https://groups.google.com/g/sage-devel/c/ba9u_As3T4s/m/7J-bzYXgBQAJ.

This should be related to #17713 and in particular #24523, and also #24456.

Of course, there can be added more for further "granularity". This is just a first attempt to start somewhere.

CC: @videlec @tscrim @mkoeppe

Component: categories

Author: Michael Jung

Branch/Commit: public/add_exact_field_category @ 17a3de7

Issue created by migration from https://trac.sagemath.org/ticket/31199

[mjungmath]

Branch: public/add_exact_field_category

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

cc8f76b	Trac #31196: code improvements
1572085	Trac #31196: if logic error
10a72b6	add Numerical and Exact fields as category

[sagetrac-git]

Commit: 10a72b6

[sagetrac-git]

Changed commit from 10a72b6 to 17a3de7

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

17a3de7

add Numerical and Exact fields as category

[mkoeppe]

comment:6

Sage development has entered the release candidate phase for 9.3. Setting a new milestone for this ticket based on a cursory review of ticket status, priority, and last modification date.