docs: update link to schematics schema (angular#41258)

PREVIOUSLY:
The https://angular.io/guide/schematics#configuring-cli-schematics page has a link to "app" schematic specifically and to a version 7.

NOW:
The https://angular.io/guide/schematics#configuring-cli-schematics page links to the latest version of schematics (all of them, not just the "app" schematic) to let the reader snoop around a bit.
PR Close angular#41258

Author: sryzycki

aio/content/guide/schematics.md

@@ -33,7 +33,7 @@ A JSON schema associated with a schematic tells the Angular CLI what options are
 These defaults can be overridden by providing a different value for an option on the command line.
 See [Workspace Configuration](guide/workspace-config) for information about how you can change the generation option defaults for your workspace.
 
-The JSON schemas for the default schematics used by the CLI to generate projects and parts of projects are collected in the package [`@schematics/angular`](https://raw.githubusercontent.com/angular/angular-cli/v7.0.0/packages/schematics/angular/application/schema.json).
+The JSON schemas for the default schematics used by the CLI to generate projects and parts of projects are collected in the package [`@schematics/angular`](https://github.com/angular/angular-cli/tree/master/packages/schematics/angular).
 The schema describes the options available to the CLI for each of the `ng generate` sub-commands, as shown in the `--help` output.
 
 ## Developing schematics for libraries