Migration: mention the removal of `.rounded-sm/lg` utilities (#32758)
Migration: mention the removal of `.rounded-sm/lg` utilities (#32758)

* Changes made in migration.md file of documentation

Added information about the removal of `.rounded-sm` and `.rounded-lg`.
And addition of `.rounded-0` to `.rounded-3`

* Moved the edited line

Added `rounded-0` to `rounded-3` under  v5.0.0-alpha3

* Moved correctly

* Added link

Added link to issue #31687

* docs(migration): last typo thinggies

* Update migration.md

Co-authored-by: Gaël Poupard <6358a35539697f127c602c4bf1c174c0714ad65d@users.noreply.github.com>
Co-authored-by: XhmikosR <b60f67e10123951b393d9ba15dcf79efc14744bb@gmail.com>
GerHobbelt/bootstrap,twbs/bootstrap,inway/bootstrap,GerHobbelt/bootstrap,coliff/bootstrap,coliff/bootstrap,twbs/bootstrap,tjkohli/bootstrap,tjkohli/bootstrap,inway/bootstrap,m5o/bootstrap,inway/bootstrap,m5o/bootstrap,GerHobbelt/bootstrap