Docs: Error Fix

Fixed Sphinx errors and expired links, used Intersphinx where possible.

Change-Id: I0d57fc49fdc5c3704d26a88a8c978f7cb72e2374
Signed-off-by: Elena Uziunaite <elena.uziunaite@arm.com>
diff --git a/docs/index.rst b/docs/index.rst
index 3e74f3a..b3534ef 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -2,8 +2,6 @@
 Trusted Firmware-M Extras
 ################################
 
-.. raw:: html
-
 The Trusted Firmware-M (TF-M) Extras repository is the extension of the TF-M
 main repository to host the examples, demonstrations, third-party modules,
 third-party secure partitions, etc.
@@ -12,7 +10,7 @@
 License
 *******
 
-The default license of new source code in this repository is :doc:`BSD 3-clause <license>`.
+The default license of new source code in this repository is `BSD 3-clause <https://git.trustedfirmware.org/TF-M/tf-m-extras.git/tree/license.rst>`_.
 
 Some source files are contributed by the third-parties or derived from the
 external projects. A license file should be included in the root folder of these
@@ -30,7 +28,7 @@
 Contribute to this repository
 *****************************
 
-Refer to `contributing process <https://trustedfirmware-m.readthedocs.io/en/latest/contributing/contributing_process.html>`_
+Refer to :doc:`contributing process <TF-M:contributing/contributing_process>`
 for the TF-M general contribution guideline.
 
 Please contact `TF-M development mailing list <https://lists.trustedfirmware.org/mailman3/lists/tf-m.lists.trustedfirmware.org>`_
@@ -50,8 +48,8 @@
   mitigate known security vulnerabilities.
 
 - List the example and secure partition in
-  :doc:`example readme <examples/examples_readme>` and
-  :doc:`secure partition readme <partitions/partitions_readme>` respectively.
+  :doc:`example readme <examples/examples>` and
+  :doc:`secure partition readme <partitions/partitions>` respectively.
 
    - Each example/secure partition shall specify the following information