docs(table): add note about MatTableDataSource usage (#16933)
docs(table): add note about MatTableDataSource usage (#16933)

Adds a note to the `MatTableDataSource` docs to be more explicit about what the intentions behind the data source are.
jelbourn/material2,andrewseguin/material2,Jefiozie/material2,andrewseguin/material2,andrewseguin/material2,Jefiozie/material2,andrewseguin/material2,josephperrott/material2,DevVersion/material2,crisbeto/material2,jelbourn/material2,josephperrott/material2,jelbourn/material2,DevVersion/material2,DevVersion/material2,josephperrott/material2,crisbeto/material2,Jefiozie/material2,mmalerba/material2,josephperrott/material2,mmalerba/material2,jelbourn/material2,Jefiozie/material2,mmalerba/material2,josephperrott/material2,crisbeto/material2,DevVersion/material2,mmalerba/material2,angular/components,angular/components,angular/components,jelbourn/material2,mmalerba/material2,Jefiozie/material2,angular/components,crisbeto/material2,DevVersion/material2,andrewseguin/material2