docs(search): set minimum length to 2

With the minimum search length set to 3, it was not possible to search for `$q`.
Changing this to 2 fixes that without really upsetting the search display, since we
only display the first 40 API and 14 non-API items anyway.

Closes #3078
docs(search): fix search submit functionality

When the search input box was submitted (i.e. by pressing enter) the
app was supposed to take you to the first item but this was not happening.
It turns out the app was just reading the wrong property for the path to
the item.

Closes #3078
docs(guide/css-styling): tiny grammar fix

Closes #5443
docs(guide/directives): improve links to isolate scope docs

Link "isolate scope" to "Directive Definition object" section

Closes #7484
chore(release): publish ngMessages to bower
fix($compile): pass transcludeFn down to nested transclude directives

If you have two directives that both expect to receive transcluded content
the outer directive works but the inner directive never receives a
transclusion function. This only failed if the first transclude directive
was not the first directive found in compilation.

Fixes #7240
Closes #7387