rust: Rename the `Revlog::get_node_rev` method to `rev_from_node`...
rust: Rename the `Revlog::get_node_rev` method to `rev_from_node`
This better describes the input and outputs of this method.
Also rewrite the doc-comment, which seemed to have been left from copy-paste
of another method.
Differential Revision:
https://phab.mercurial-scm.org/D11415