feat(combinatorics/configuration): Define `line_count` and `point_count` (#10884)
feat(combinatorics/configuration): Define `line_count` and `point_count` (#10884)

Adds definitions for the number of lines through a given point and the number of points through a given line.



Co-authored-by: tb65536 <25c750517795e47f172dc8c552ed72c7de260bd4@users.noreply.github.com>

leanprover-community/mathlib,leanprover-community/mathlib