docs(material/core): Add a brief overview that refers users to the API docs (#22773)

mmalerba · wagnermaciel · commit 8c6028665674 · 2021-05-24T20:13:55.000-07:00
This will allow us to publish a section on the docs site for `@angular/material/core`. (cherry picked from commit 1305587)
diff --git a/src/material/core/core.md b/src/material/core/core.md
@@ -0,0 +1,2 @@
+The `@angular/material/core` package contains common components and services used by multiple other
+components in the library. See the API tab for a listing of components and classes available.

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	+The `@angular/material/core` package contains common components and services used by multiple other
	`2`	`+components in the library. See the API tab for a listing of components and classes available.`