The install and upgrade guides tell readers to pin the release candidate with `--save-exact`

[armando-navarro]

#3765 added a step to docs/version-21-upgrade.md and docs/install-and-setup.md: after ng update or ng add with @angular/fire@next, run npm install --save-exact @angular/fire@next. It was needed because the ^21.0.0-rc.1 range those commands write resolved to a canary release, 21.0.0-rc.1-canary.95b3de1.

That is no longer the case. The 25 canary releases that outranked 21.0.0-rc.1 are now deprecated on npm, and npm skips a deprecated version when a non-deprecated one also matches. Re-run on real apps:

• ng update @angular/core@21 @angular/cli@21 @angular/fire@next from Angular 20 writes ^21.0.0-rc.1 and installs 21.0.0-rc.1.
• ng add @angular/fire@next on Angular 21 installs 21.0.0-rc.1 and writes it exactly.

The extra step and its explanation can come out of both guides.