docs(general): correct bower version separator from '@' to '#'

[guillaumegarcia13]

What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

Docs update

What is the current behavior? (You can also link to an open issue here)

bower syntax is incorrect, the docs says '@' instead of '#' to specify version

What is the new behavior (if this is a feature change)?

bower syntax is corrected

Does this PR introduce a breaking change?

No (considering it's documentation)

Please check if the PR fulfills these requirements

• The commit message follows our guidelines: https://github.com/angular/angular.js/blob/master/CONTRIBUTING.md#commit-message-format
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

Other information:

[gkalpak]

Is this new? I'm pretty sure @ used to work too.

[guillaumegarcia13]

@gkalpak I am no bower expert but I did try the version in the docs with the given syntax and failed miserably... Took me a couple of minutes to realize the angular docs were in question.

The bower version using '#' seems the way to go now, I don't know about earlier.
https://bower.io/docs/api/#install

I guess it can be confusing since npm is using the different '@' syntax.
https://docs.npmjs.com/cli/install