fixes typo.
## Description This PR introduces documentation for recently merged feature: external workspaces. https://github.com/coder/coder/pull/19285 https://github.com/coder/coder/pull/19286 https://github.com/coder/coder/pull/19287 https://github.com/coder/coder/pull/19288 --------- Co-authored-by: Atif Ali <atif@coder.com>