[Documentation]: Missing documentation about NaggyMock

[carlosgalvezp]

Describe the issue

In the section "The Nice, the Strict and the Naggy", it only talks about the Nice and Strict mocks, but no mention about Naggy. This should be added.

Note: I'm aware there's documentation about Naggy in the "Mocking Reference", but I still think it should also be added to the above section, otherwise it's very confusing.

Steps to reproduce the problem

Browse the docs and find no mention of the NaggyMock

What version of GoogleTest are you using?

Trunk.

What operating system and version are you using?

N/A

What compiler and version are you using?

N/A

What build system are you using?

N/A

Additional context

No response