Update package.json

Add description for new setting.

Author: sql-koala

package.json

@@ -739,6 +739,11 @@
           "markdownDescription": "Enable the [Surround](https://github.com/tpope/vim-surround) plugin for Vim.",
           "default": true
         },
+        "vim.disableDefaultPluginMappings": {
+          "type": "boolean",
+          "markdownDescription": "For users of custom keyboard layouts. Disable default keymappings starting with c/d/y. At present only affects surround.",
+          "default": false
+        },
         "vim.argumentObjectSeparators": {
           "type": "array",
           "items": {