mathlib

a813cf5c - chore(algebra/algebra/spectrum): move `exists_spectrum_of_is_alg_closed_of_finite_dimensional` (#10919)

chore(algebra/algebra/spectrum): move `exists_spectrum_of_is_alg_closed_of_finite_dimensional` (#10919) Move a lemma from `field_theory/is_alg_closed/basic` into `algebra/algebra/spectrum` which belongs in this relatively new file. Also, rename (now in `spectrum` namespace) and refactor it slightly; and update the two references to it accordingly. - [x] depends on: #10783 Co-authored-by: Vierkantor <vierkantor@vierkantor.com>