Docs: Remove mentions of overlapping patterns
Docs: Remove mentions of overlapping patterns

This information is all outdated, the current implementation doesn't
check for overlap between patterns. Instead it's looking at how the
overlap between the scrutinee type and each pattern, sequentially.

lampepfl/dotty,dotty-staging/dotty,dotty-staging/dotty,sjrd/dotty,sjrd/dotty,lampepfl/dotty,som-snytt/dotty,dotty-staging/dotty,lampepfl/dotty,sjrd/dotty,som-snytt/dotty,dotty-staging/dotty,som-snytt/dotty,sjrd/dotty,lampepfl/dotty,som-snytt/dotty,sjrd/dotty,som-snytt/dotty,lampepfl/dotty,dotty-staging/dotty