Merge pull request #203 from antmicro/160-fix-sphinx-warnings

Removed duplicated keys from previous.rst
diff --git a/docs/previous.rst b/docs/previous.rst
index 2c87fcb..887518a 100644
--- a/docs/previous.rst
+++ b/docs/previous.rst
@@ -29,13 +29,9 @@
         process. It stood for the "8th generation" of the SONOS technology
         developed originally by Cypress.
-    :lib_process:`s8phrc`
         The name for using 180nm technology on the 130nm process.
-    :lib_process:`s8phirs`
         The base process.  5 metal layer backend stack, 16V devices, deep