ptr_aligment_type: add more APIs

[GrigorenkoPV]

As per #102070 (comment)

Tracking issue: #102070

Mostly duplicating methods that previously worked with usize-represented alignments.

Naming follows a convention of align: usize, alignment: Alignment.

Based on top of #148769

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[GrigorenkoPV]

Conflicts with #148769, let's wait for that first

[joboet]

I really prefer the current spelling of Alignment::of as opposed to alignment_of and therefore would like to suggest adding of_val and of_val_raw as associated methods instead of free-standing functions in mem.

[scottmcm]

This rename is so big that github hides it by default.

Please make this PR just the api addition. If you also want to rename this field, that's fine, but please do it separately because of how much it touches.

[scottmcm]

fix: you don't need the return, the true, or the false here.

[rust-log-analyzer]

A job failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

  PR_CI_JOB: 1
  SKIP_SUBMODULES: src/gcc
  IMAGE: tidy
##[endgroup]
error: PRs changing the `nightly` channel should be sent to the `master` branch!
##[error]Process completed with exit code 1.
##[group]Run echo "disk usage:"
echo "disk usage:"
df -h
shell: /usr/bin/bash --noprofile --norc -e -o pipefail {0}

[GrigorenkoPV]

Looks like the failure is due to the rename of master branch and is unrelated to this PR