decouple fixed-pitch from default

resolves issue described in https://github.com/protesilaos/ef-themes/issues/9#issuecomment-1264202451

appearance.org

@@ -95,7 +95,7 @@ Here is a set of functions for [[id:cce/cce][CCE]] which set up my font preferen
     (with-eval-after-load 'org (set-face-attribute 'org-block nil :inherit 'fixed-pitch))
     (with-eval-after-load 'linum (set-face-attribute 'linum nil :inherit 'default :height size)))
   (set-face-attribute 'default nil        :height size)
-  (set-face-attribute 'fixed-pitch nil    :inherit 'default)
+  (set-face-attribute 'fixed-pitch nil)
   (set-face-attribute 'variable-pitch nil :slant 'oblique :height size)
   (cce/enable-ipaex-font (/ size 3)))
 #+end_src

applications_i_use.org

@@ -118,7 +118,7 @@ in
     #       ${python3}/bin/python3 make_release.py Python3
     #     '';
     # })
-  ] +++ [
+  ] ++ [
     zip
     unzip
     bind.dnsutils