Python: drop python.majorVersion

Drop `python.majorVersion`. For Python language version, use `python.pythonVersion`.
For implementation version, use `python.sourceVersion`.

Some expressions were broken. Those that were identified were fixed.

fixup major

pkgs/applications/networking/instant-messengers/profanity/default.nix

@@ -62,7 +62,7 @@ stdenv.mkDerivation rec {
     ++ optionals pythonPluginSupport [ "-I${python}/include/${python.libPrefix}" ];
 
   LDFLAGS = [ ]
-    ++ optionals pythonPluginSupport [ "-L${python}/lib" "-lpython${python.majorVersion}m" ];
+    ++ optionals pythonPluginSupport [ "-L${python}/lib" "-l${python.libPrefix}" ];
 
   meta = {
     description = "A console based XMPP client";