Improve docs "Understanding Angular-Directives-Attribute Directives"
In `highlight.directive.1.ts`, add the `private` keyword for `el` property
to make it correct and consistent with subsequent examples.
For section "Setting the value with user input", add a step to tell the
reader change the method `onMouseEnter`, thus more readable.
For section "Binding to a second property", delete the aliase for the
`Input` property, and changes the name back to `appHighlight` in the code
to make it consistent with the whole tutorial.
PR Close#44628
ngNonBindable documentation was not present, on docs site added documentation for ngNonBindable. With this template primitive, Angular won't
evaluate expressions in elements.
Fixes#28577Fixes#19497
PR Close#36560
This commit updates the docs examples to be compatible with the
`import-spacing` tslint rule.
This is in preparation of updating the docs examples `tslint.json` to
match the one generated for new Angular CLI apps in a future commit.
PR Close#38143
