Only directive blocks headers from being in TOC

[roxannemoslehi]

Subject: Only directive blocks headers from being in TOC

Problem

• If you use the "only directive" to flag off some content, any headers inside that directive won't show up in the TOC.

Procedure to reproduce the problem

**CONTENTS:**

.. contents::
   :local:
   :depth: 1

Title1
======

Some content. 

.. only:: internal

   Title2
   ======

   Some more content.

Title3
======

Even more content.

Error logs / results

When you run:

sphinx-build -b html -t internal ....

The generated TOC at the top of the page looks like this:

CONTENTS:

• Title1
• Title3

Expected results

What we really want is this:

CONTENTS:

• Title1
• Title2
• Title3

The "Title2" header should only be missing from the TOC if I run something like sphinx-build -b html -t external so using a -t flag other than internal.

[tk0miya]

Sorry, "only" directive was not designed to control section. This behavior is specification.
(refs: #2132)