doc: drop explicit :tech: role

docs/source/tutorial/tutorial04.rst

@@ -144,14 +144,14 @@ I Need my Report!
      EOF
 
   The shell will put the data between the first ``EOF`` and the second
-  ``EOF`` as the :tech:`stdin` of the :command:`cat` process.
+  ``EOF`` as the `stdin` of the :command:`cat` process.
 
 **Junior**
 
   OK, I understand. That's cool, by the way.
 
   So, if I want to use this with *Kapow!*, I have to make it read the script
-  from :tech:`stdin`.  To do this I know that I have to put a :nref-option:`-` at the end.
+  from `stdin`.  To do this I know that I have to put a :nref-option:`-` at the end.
 
   Let me try:
 

docs/source/tutorial/tutorial05.rst

@@ -200,7 +200,7 @@ Sharing the Stats
      because the body can be so big that *Kapow!* is forced to start sending it
      out.
   2. In cases where you want to set a small piece of data (like the header), it
-     is better not to use :tech:`stdin`.  *Kapow!* provides a secondary syntax
+     is better not to use `stdin`.  *Kapow!* provides a secondary syntax
      for these cases:
 
      .. code-block:: console