mathlib

e8ca35f1 - chore(linear_algebra/matrix/block): remove the `_matrix` suffix from `matrix.block_triangular_matrix` (#16155)

chore(linear_algebra/matrix/block): remove the `_matrix` suffix from `matrix.block_triangular_matrix` (#16155) The same is done for the primed version. There's no need to have the word `matrix` in this definition twice.