Improve linear algebra documentation

[emikelsons]

• Improved linear algebra documentation
• Fixed a broken doi link
  I wanted to add more textbook references, but almost none were referenced in the section.
  Any suggestions for relevant textbooks for this section are welcome and I will add them. Ideally, I would like to add a couple more before this is merged. @fieker @thofma Do you have any textbook suggestions for the linear algebra section of the docs?
  This is addressing Improve the documentation on linear algebra #2078

[lgoettgens]

Ok, so the issue with this particular one is the following:

• [Matrix functionality](@ref) can either reference https://docs.oscar-system.org/dev/AbstractAlgebra/matrix/#Matrix-functionality or https://docs.oscar-system.org/dev/Nemo/matrix/#Matrix-functionality
• [Basic matrix functionality](@ref) can either reference https://docs.oscar-system.org/dev/AbstractAlgebra/matrix/#Basic-matrix-functionality or https://docs.oscar-system.org/dev/AbstractAlgebra/matrix_algebras/#Basic-matrix-functionality
• Due to Documenter interals, it does not complain about the above (see "Header with slug '$slug' is not unique" error should always be thrown JuliaDocs/Documenter.jl#2668), and instead tries to parse Matrix-functionality as a function signature, thus ending up with a reference to a method of -.

Easiest solution:
Do a PR to AbstractAlgebra that puts an @id to the header (as in https://github.com/Nemocas/AbstractAlgebra.jl/blob/91a641d16373996c2843c8ef43061aae07c65426/docs/src/linear_solving.md?plain=1#L5), and then reference that here.
I'll do the PR immediately: Nemocas/AbstractAlgebra.jl#2043

[emikelsons]

Ok, so the issue with this particular one is the following:

* `[Matrix functionality](@ref)` can either reference https://docs.oscar-system.org/dev/AbstractAlgebra/matrix/#Matrix-functionality or https://docs.oscar-system.org/dev/Nemo/matrix/#Matrix-functionality

* `[Basic matrix functionality](@ref)` can either reference https://docs.oscar-system.org/dev/AbstractAlgebra/matrix/#Basic-matrix-functionality or https://docs.oscar-system.org/dev/AbstractAlgebra/matrix_algebras/#Basic-matrix-functionality

* Due to Documenter interals, it does not complain about the above (see [`"Header with slug '$slug' is not unique"` error should always be thrown JuliaDocs/Documenter.jl#2668](https://github.com/JuliaDocs/Documenter.jl/issues/2668)), and instead tries to parse `Matrix-functionality` as a function signature, thus ending up with a reference to a method of `-`.

Easiest solution: Do a PR to AbstractAlgebra that puts an @id to the header (as in https://github.com/Nemocas/AbstractAlgebra.jl/blob/91a641d16373996c2843c8ef43061aae07c65426/docs/src/linear_solving.md?plain=1#L5), and then reference that here. I'll do the PR immediately: tbd

Good find, I was unsure where to look next after the debugger was of no help

[lgoettgens]

Good find, I was unsure where to look next after the debugger was of no help

What I basically did: Dev Documenter, add some @debug statements, build Oscar docs, find nothing, add more debug statements, build docs again, crash vscode when searching through some few GB of logs, remove some debug statements, ... repeat until I basically understood most parts of the cross-referencing internals.

[lgoettgens]

This branch now works locally if used together with Nemocas/AbstractAlgebra.jl#2043. So we need to wait for the AA release now

[lgoettgens]

If I see correctly, this reference is never mentioned. Is this on purpose?

[emikelsons]

This one is not mentioned in the intro, no. In the intro I wanted to add only textbook references or alike

[thofma]

Maybe some standard text a la "Linear Algebra" by Lang?

[emikelsons]

Maybe some standard text a la "Linear Algebra" by Lang?

I have now added this reference and this pr can now be merged, provided the tests pass