fix(docs): menu toggle is not open on the current page

[8lueberry]

Fix docs nav toggle to open the current page when refreshing the page or navigating directly to a section.

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[8lueberry]

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[8lueberry]

Bug description: When navigating to https://material.angularjs.org/latest/demo/whiteframe for example, the menu is not selected on the left (the toggle icon is correct, but the sub menu is not shown).

Wrapped getTargetHeight() in a $timeout in order to get the proper ul height (instead of 0).