docs: code example styles not conforming to docs style guide

I’m submitting a…

[ ] Regression (a behavior that used to work and stopped working in a new release)
[ ] Bug report  
[ ] Performance issue
[ ] Feature request
[x] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question
[ ] Other... Please describe:

Current behavior

For terminal input and output, put the content between <code-example> tags, set the CSS class to code-shell, and set the language attribute to sh

Multiple code examples do not conform to this guide.

Expected behavior

<code-example language="sh" class="code-shell"> should be used for all code examples.

[ajitsinghkaler]

by platform, I meant the angular.io website

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