Allow copy-pasting dev-server-token (#11992)

Release Notes:

- N/A

assets/keymaps/default-linux.json

@@ -191,6 +191,12 @@
       "ctrl-shift-enter": "editor::NewlineBelow"
     }
   },
+  {
+    "context": "Markdown",
+    "bindings": {
+      "ctrl-c": "markdown::Copy"
+    }
+  },
   {
     "context": "AssistantPanel",
     "bindings": {

assets/keymaps/default-macos.json

@@ -207,6 +207,12 @@
       "ctrl-shift-enter": "editor::NewlineBelow"
     }
   },
+  {
+    "context": "Markdown",
+    "bindings": {
+      "cmd-c": "markdown::Copy"
+    }
+  },
   {
     "context": "AssistantPanel", // Used in the assistant crate, which we're replacing
     "bindings": {