Make `-S` an alias of `--start` in changes query REST API

The option had been added with the name `-S`.  Change the name
to `--start` with `-S` as an alias, making it consistent with the
naming in other REST APIs.

Add the option to the documentation.

Remove the documentation of `-P` and `-N`. These options only exist
to support online reindexing from clients with outdated JS, and are
deprecated. Keeping them in the documentation will potentially
cause confusion.

Bug: Issue 2878
Change-Id: I992acf4a3d1aeebb1ef40c6fed1afcb0fe26fa92
2 files changed