drawio: add 'draw.io' to description to improve search discoverability

pkgs/applications/graphics/drawio/default.nix

···
   ];
 
   meta = with lib; {
-    description = "Desktop application for creating diagrams";
+    description = "Desktop version of draw.io for creating diagrams";
     homepage = "https://about.draw.io/";
     license = with lib.licenses; [
       # The LICENSE file of https://github.com/jgraph/drawio claims Apache License Version 2.0 again since https://github.com/jgraph/drawio/commit/5b2e73471e4fea83d681f0cec5d1aaf7c3884996

pkgs/applications/graphics/drawio/headless.nix

···
   meta = with lib; {
     description = "xvfb wrapper around drawio";
     longDescription = ''
-      A wrapper around drawio for running in headless environments.
+      A wrapper around drawio (draw.io) for running in headless environments.
       Runs drawio under xvfb-run, with configuration going to a temporary
       directory.
     '';