`package` package opened when input box canceled

The following line doesn't account for cancellation:

https://github.com/bengreenier/vscode-node-readme/blob/89b2d6fdb324e55870fd15eee599dabc80136ad2/src/commands/showReadme.ts#L21

In theory that should pass `findReadme(undefined)` then attempt to open `https://npmjs.org/package/undefined` (I guess) but instead opens `https://npmjs.org/package/` which npm interprets as the `package` package.

A related issue is the key binding should only be triggered when `"editorLangId == 'javascript' || ..."`.

Start with src/commands/showReadme.ts at the linked line and trace what happens when the input box is canceled. Also inspect the extension's keybinding configuration for the editorLangId condition. Done means cancellation no longer opens the npm package URL without a name, and the key binding is limited to the intended languages.

Written by the indexing model from the issue text.