message: Clarify that [replace] requires a version number.
  Closes
diff: @@ -1000,11 +1000,11 @@ other copies. The syntax is similar to the `[dependencies]` section:
  Each key in the `[replace]` table is a [package ID
  specification](pkgid-spec.md), which allows arbitrarily choosing a node in the
  -dependency graph to override. The value of each key is the same as the
  -`[dependencies]` syntax for specifying dependencies, except that you can't
  -specify features. Note that when a crate is overridden the copy it's overridden
  -with must have both the same name and version, but it can come from a different
  -source (e.g., git or a local path).
  +dependency graph to override (the 3-part version number is required). The
  +value of each key is the same as the `[dependencies]` syntax for specifying
  +dependencies, except that you can't specify features. Note that when a crate
  +is overridden the copy it's overridden with must have both the same name and
  +version, but it can come from a different source (e.g., git or a local path).
  More information about overriding dependencies can be found in the [overriding
  dependencies][replace] section of the documentation.
  