Apply suggestions from code review

Co-authored-by: Josh Triplett <[email protected]>

Author: arlosi

posts/2022-06-16-sparse-registry-testing.md

@@ -7,8 +7,8 @@ team: The Cargo Team <https://www.rust-lang.org/governance/teams/dev-tools#cargo
 
 The Cargo nightly [`sparse-registry`][sparse-registry] feature is ready for testing. The
 feature causes Cargo to access the crates.io index over HTTP, rather than git. It can
-provide a significant performance improvement, especially if the git index is
-out-of-date or not yet cloned.
+provide a significant performance improvement, especially if the local copy of
+the git index is out-of-date or not yet cloned.
 
 ## Overview
 To try it out, add the `-Z sparse-registry` flag on `nightly-2022-06-20` or newer build
@@ -37,7 +37,7 @@ and clients must download the entire index. The HTTP index only requires downloa
 metadata for crates in your dependency tree. 
 
 The performance improvement for clients should be especially noticeable in CI
-environments, where no local cache of the index exists.
+environments, particularly if no local cache of the index exists.
 
 On the server side, the HTTP protocol is much simpler to cache on a CDN, which improvies
 scalability and reduces server load.