docs(angular) : add cd instruction to move inside workspace directory (#28135)

`npx nx serve angular-store` this would not work if the user does not
move to the directory first.

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Fixes #

Co-authored-by: Isaac Mann <isaacplmann@users.noreply.github.com>

docs/shared/tutorials/angular-monorepo.md

@@ -118,6 +118,7 @@ The [`nx.json` file](/reference/nx-json) contains configuration settings for Nx
 To serve your new Angular application, just run:
 
 ```shell
+cd angular-monorepo
 npx nx serve angular-store
 ```