message: Remove outdated stability note
  Closes
diff: @@ -187,10 +187,9 @@ example:
  of the crate to avoid blocking on the bug fix getting merged.
  These scenarios are currently all solved with the [`[patch]` manifest
  -section][patch-section]. Note that the `[patch]` feature is not yet currently
  -stable and will be released on 2017-08-31. Historically some of these scenarios
  -have been solved with [the `[replace]` section][replace-section], but we'll
  -document the `[patch]` section here.
  +section][patch-section]. Historically some of these scenarios have been solved
  +with [the `[replace]` section][replace-section], but we'll document the `[patch]`
  +section here.
  [patch-section]: reference/manifest.html#the-patch-section
  [replace-section]: reference/manifest.html#the-replace-section
  