bug(Button): container shape override not working + update docs

[richardsengers]

Description

When setting a container shape like medium or small, the layout off the button is a square

From m3 site:
For example, by default, buttons are mapped to the shape style “full.” If your product requires a smaller amount of roundedness, it can be remapped to the small or medium style in shape scale.

I think the docs should also be updated so we know which button type has which setting (is the raised button the protected-* setting?)
And offcourse which settings we can use. I now have to search https://m3.material.io/ to find out what shape settings I can use

This is the only thing the material docs say about a shape, but it apears we can use none, small, medium, etc as a value

Reproduction

1. https://stackblitz.com/edit/dqdmtecp?file=src%2Fstyles.scss
2. change the the filled-container-shape to one of the available shape settings
   https://m3.material.io/styles/shape/overview

Expected Behavior

Make button rounded confirm the https://m3.material.io/styles/shape/overview

Actual Behavior

square buttons are shown

Environment

Angular CLI: 19.0.5
Node: 22.3.0
Package Manager: yarn 1.22.17
OS: win32 x64

Angular: 19.0.4
... animations, common, compiler, compiler-cli, core, forms
... language-service, platform-browser, platform-browser-dynamic
... platform-server, router, service-worker

Package Version

@angular-devkit/architect 0.1900.5 (cli-only)
@angular-devkit/build-angular 19.0.5
@angular-devkit/core 19.0.5
@angular-devkit/schematics 19.0.5
@angular/cdk 19.0.3
@angular/cli 19.0.5
@angular/material 19.0.3
@angular/material-date-fns-adapter 19.0.3
@schematics/angular 19.0.5
rxjs 7.8.1
typescript 5.6.3
zone.js 0.15.0

[crisbeto]

The shape needs to be a pixel value.