helix handles C source better

homes/modules/editor/helix.nix

@@ -131,6 +131,8 @@
         }
         {
           name = "c";
+          file-types = ["c" "h"]; # use .hpp for C++
+          auto-format = false;
           formatter.command = "${pkgs.clang-tools}/bin/clang-format";
           language-servers = ["clangd"];
         }