sphinx: rename top level document in each manual

It is more common to call the top level document index.rst. This is
what this patch is doing, along with all required references fixup.

(From yocto-docs rev: 2cea7fbba9210479fc0387d7e1b80da9885558f0)

Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/dev-manual/dev-manual-common-tasks.rst

@@ -3644,7 +3644,7 @@ build host running Linux.
 
    -  For information on how to build an image using
       :term:`Toaster`, see the
-      :doc:`../toaster-manual/toaster-manual`.
+      :doc:`../toaster-manual/index`.
 
    -  For information on how to use ``devtool`` to build images, see the
       ":ref:`sdk-manual/sdk-extensible:using \`\`devtool\`\` in your sdk workflow`"
@@ -3653,7 +3653,7 @@ build host running Linux.
 
    -  For a quick example on how to build an image using the
       OpenEmbedded build system, see the
-      :doc:`../brief-yoctoprojectqs/brief-yoctoprojectqs` document.
+      :doc:`../brief-yoctoprojectqs/index` document.
 
 The build process creates an entire Linux distribution from source and
 places it in your :term:`Build Directory` under
@@ -3728,7 +3728,7 @@ The following figure and list overviews the build process:
    kernels built by the OpenEmbedded build system are placed in the
    Build Directory in ``tmp/deploy/images``. For information on how to
    run pre-built images such as ``qemux86`` and ``qemuarm``, see the
-   :doc:`../sdk-manual/sdk-manual` manual. For
+   :doc:`../sdk-manual/index` manual. For
    information about how to install these images, see the documentation
    for your particular board or machine.
 

documentation/dev-manual/dev-manual-intro.rst

@@ -31,13 +31,13 @@ This manual provides the following:
 This manual does not provide the following:
 
 -  Redundant Step-by-step Instructions: For example, the
-   :doc:`../sdk-manual/sdk-manual` manual contains detailed
+   :doc:`../sdk-manual/index` manual contains detailed
    instructions on how to install an SDK, which is used to develop
    applications for target hardware.
 
 -  Reference or Conceptual Material: This type of material resides in an
    appropriate reference manual. For example, system variables are
-   documented in the :doc:`../ref-manual/ref-manual`.
+   documented in the :doc:`../ref-manual/index`.
 
 -  Detailed Public Information Not Specific to the Yocto Project: For
    example, exhaustive information on how to use the Source Control
@@ -52,7 +52,7 @@ supplemental information is recommended for full comprehension. For
 introductory information on the Yocto Project, see the
 :yocto_home:`Yocto Project Website <>`. If you want to build an image with no
 knowledge of Yocto Project as a way of quickly testing it out, see the
-:doc:`../brief-yoctoprojectqs/brief-yoctoprojectqs` document.
+:doc:`../brief-yoctoprojectqs/index` document.
 
 For a comprehensive list of links and other documentation, see the
 ":ref:`ref-manual/resources:links and related documentation`"

documentation/dev-manual/dev-manual-start.rst

@@ -344,7 +344,7 @@ going to use BitBake, see the
 section. If you are going
 to use the Extensible SDK, see the ":doc:`../sdk-manual/sdk-extensible`" Chapter in the Yocto
 Project Application Development and the Extensible Software Development
-Kit (eSDK) manual. If you want to work on the kernel, see the :doc:`../kernel-dev/kernel-dev`. If you are going to use
+Kit (eSDK) manual. If you want to work on the kernel, see the :doc:`../kernel-dev/index`. If you are going to use
 Toaster, see the ":doc:`../toaster-manual/toaster-manual-setup-and-use`"
 section in the Toaster User Manual.