Docs: Add note on verific

Having a verific license does not provide access to the verific frontend.

docs/source/using_yosys/more_scripting/load_design.rst

@@ -27,6 +27,14 @@ keyword: Frontends
 .. todo:: more info on other ``read_*`` commands, also is this the first time we
    mention verific?
 
+.. note::
+
+   The Verific frontend for Yosys, which provides the :cmd:ref:`verific`
+   command, requires the commercial `Tabby CAD Suite`_.  This is not the same as
+   simply having a Verific license when using Yosys.
+
+.. _Tabby CAD Suite: https://www.yosyshq.com/tabby-cad-datasheet
+
 Others:
 
 - :doc:`/cmd/read`

docs/source/using_yosys/synthesis/memory.rst

@@ -697,6 +697,9 @@ TDP with multiple read ports
 Patterns only supported with Verific
 ------------------------------------
 
+The following patterns are only supported when Yosys is built with the Verific
+front-end.
+
 Synchronous SDP with write-first behavior via blocking assignments
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~