The online documentation is for the most recent release (currently release R2018a) and so may include functions and features that are not present in your installation if you're using an older release. Refer to the documentation included in your installation for a list of functions and features that are present in the release you're using.
The note at the bottom of the documentation page for the googlenet network says it was introduced in release R2017b, so I suspect that example was introduced in release R2017b or later as well. The documentation for inceptionv3 states it was introduced in release R2017b as well. If you want to use googlenet or inceptionv3 you will need to upgrade to release R2017b or later and have Neural Network Toolbox installed.