Add Redirect form "from" field description implies the path needs to exist internally, but it doesn't

Enter an internal Drupal path or path alias to redirect (e.g. node/123 or taxonomy/term/123). Fragment anchors (e.g. #anchor) are not allowed.

The description (above) on the "From" field (redirect source) on the "Add Redirect" form implies that the path needs to exist internally. This can be confusing for a user if they're trying to enter redirects after, say, a site migration from their old urls. I propose the following change to the description:

Enter a path to redirect. The path can be an internal Drupal path or path alias (e.g. node/123 or taxonomy/term/123), or a non-existent path (e.g. an old url after a site migration).
Fragment anchors (e.g. #anchor) are not allowed.

Patch is attached.