docs: update documentation on creating a custom material module

[ahasall]

This PR improves the precision of the documentation on creating our own custom Material NgModule.

The only requirement for this NgModule is to export Angular Material modules. Currently the documentation puts the focus on importing the Material modules.

While importing the Material modules in MyOwnCustomMaterialModule doesn't do any harm it's not necessary.

What do you think?

[juristr]

Right. But personally, especially for newcomers, it might be better to also leave the imports statement as well. Usually where this importing/exporting happens is your SharedModule, where you most probably have also a bunch of other stuff that you'd like to re-export + you might even have shared components there, using things from Angular Material, and thus the import would be required again.

So for simplicity, I'd nearly suggest changing it slightly to

"Alternatively, you can create a separate NgModule that imports and then re-exports all of the Anguar Material components that you will use in your application. By exporting them again, other modules can simply include our MyOwnCustomMaterialModule wherever Material components are needed and automatically get all of the exported Material modules. A good place for importing/exporting the application-wide Material modules is the SharedModule."

Something like this.

[ahasall]

I couldn't have said this any better.

[jelbourn]

LGTM

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}