remove special lowering for and deprecate .'

[Sacha0]

This pull request is the next step towards JuliaLang/LinearAlgebra.jl#57 after #24969 and #25083, completing items 8-12 in #24969's OP's task list. Specifically, this pull request:

1. Rewrites all remaining uses of .' in base, test, and stdlib as appropriate.
2. Removes the special lowering for .' in multiplication, left-division, and right-division expressions.
3. Deprecates .'.

Notes:

1. This pull request is based on transition linalg to Adjoint/Transpose externally #25083, from which the first twenty commits come. Only the last five commits belong to this pull request. I will rebase those commits out once transition linalg to Adjoint/Transpose externally #25083 merges. Rebased out.
2. I deprecated .' in src/julia-syntax.scm. Whether that's the best way to go about this deprecation (or instead, e.g., lower .' to some, e.g., depwarn_transpose function defined in base/deprecated.jl) I do not know, and would appreciate input from someone better versed in these things than I :).
3. I plan to write a news entry for these changes as part of a large, single news item on the A_mul_B and all that jazz LinearAlgebra.jl#57 (in a later pull request).

Thanks and best!

[Sacha0]

Rebased out the commits from #25083. Time for another round of CI roulette!

[Sacha0]

The elusive CI straight flush! 🎉

[Sacha0]

Rebased. Assuming CI approves again, I plan to merge these changes this evening PT or later. (The syntax deprecation and parser changes can be touched up in a later pull request if need be.) Best!