Docs: Section/folder for yosys source details

Move test_suites page into said folder.
Placeholder page for building with verific.

docs/source/getting_started/installation.rst

@@ -138,7 +138,8 @@ To use a compiler different than the default, use:
 
 .. seealso:: 
 
-   Refer to :doc:`/test_suites` for details on testing Yosys once compiled.
+   Refer to :doc:`/yosys_source/test_suites` for details on testing Yosys once
+   compiled.
 
 Source tree and build system
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -193,7 +194,7 @@ directories:
 
 ``tests/``
    This directory contains the suite of unit tests and regression tests used by
-   Yosys.  See :doc:`/test_suites`.
+   Yosys.  See :doc:`/yosys_source/test_suites`.
 
 The top-level Makefile includes :file:`frontends/{*}/Makefile.inc`,
 :file:`passes/{*}/Makefile.inc` and :file:`backends/{*}/Makefile.inc`. So when

docs/source/index.rst

@@ -40,6 +40,6 @@ available, go to :ref:`commandindex`.
    getting_started/index
    using_yosys/index
    yosys_internals/index
-   test_suites
+   yosys_source/index
 
    appendix

docs/source/yosys_source/build_verific.rst

@@ -0,0 +1,2 @@
+Compiling with Verific library
+------------------------------

docs/source/yosys_source/index.rst

@@ -0,0 +1,7 @@
+Yosys source details
+--------------------
+
+.. toctree::
+
+   build_verific
+   test_suites