Bug 1536103 - Add files to marionatte toctree. r=marionette-reviewers,ato

Differential Revision: https://phabricator.services.mozilla.com/D54048

--HG--
extra : moz-landing-system : lando

testing/marionette/doc/index.rst

@@ -38,14 +38,16 @@ Some further documentation can be found here:
    :maxdepth: 1
 
    Intro.md
+   Building.md
    PythonTests.md
    Protocol.md
    Contributing.md
+   NewContributors.md
+   Patches.md
    Debugging.md
    Testing.md
    Taskcluster.md
    CodeStyle.md
-   Patching.md
    SeleniumAtoms.md
    Prefs.md
    internals/index