rust: improved docstring
In the previous wording, rustfmt wanted to cut at the == which is not very
readable in my taste.
Differential Revision: https://phab.mercurial-scm.org/D5414
--- a/rust/hg-core/src/ancestors.rs Thu Dec 13 17:18:57 2018 +0800
+++ b/rust/hg-core/src/ancestors.rs Tue Dec 11 17:31:54 2018 +0100
@@ -101,9 +101,9 @@
///
/// - there's no filtering of invalid parent revisions. Actually, it should be
/// consistent and more efficient to filter them from the end caller.
-/// - we don't have the optimization for adjacent revs
-/// (case where p1 == rev-1), because it amounts to update the first element
-/// of the heap without sifting, which Rust's BinaryHeap doesn't let us do.
+/// - we don't have the optimization for adjacent revisions (i.e., the case
+/// where `p1 == rev - 1`), because it amounts to update the first element of
+/// the heap without sifting, which Rust's BinaryHeap doesn't let us do.
/// - we save a few pushes by comparing with `stoprev` before pushing
impl<G: Graph> Iterator for AncestorsIterator<G> {
type Item = Result<Revision, GraphError>;