Reflow crater chapter

Author: jieyouxu

src/tests/crater.md

@@ -1,10 +1,10 @@
 # Crater
 
-[Crater](https://github.com/rust-lang/crater) is a tool for compiling
-and running tests for _every_ crate on [crates.io](https://crates.io) (and a
-few on GitHub). It is mainly used for checking the extent of breakage when
-implementing potentially breaking changes and ensuring lack of breakage by
-running beta vs stable compiler versions.
+[Crater](https://github.com/rust-lang/crater) is a tool for compiling and
+running tests for _every_ crate on [crates.io](https://crates.io) (and a few on
+GitHub). It is mainly used for checking the extent of breakage when implementing
+potentially breaking changes and ensuring lack of breakage by running beta vs
+stable compiler versions.
 
 ## When to run Crater
 
@@ -15,16 +15,16 @@ or could cause breakage. If you are unsure, feel free to ask your PR's reviewer.
 
 The rust team maintains a few machines that can be used for running crater runs
 on the changes introduced by a PR. If your PR needs a crater run, leave a
-comment for the triage team in the PR thread. Please inform the team whether
-you require a "check-only" crater run, a "build only" crater run, or a
+comment for the triage team in the PR thread. Please inform the team whether you
+require a "check-only" crater run, a "build only" crater run, or a
 "build-and-test" crater run. The difference is primarily in time; the
-conservative (if you're not sure) option is to go for the build-and-test run.
-If making changes that will only have an effect at compile-time (e.g.,
-implementing a new trait) then you only need a check run.
+conservative (if you're not sure) option is to go for the build-and-test run. If
+making changes that will only have an effect at compile-time (e.g., implementing
+a new trait) then you only need a check run.
 
 Your PR will be enqueued by the triage team and the results will be posted when
-they are ready. Check runs will take around ~3-4 days, with the other two
-taking 5-6 days on average.
+they are ready. Check runs will take around ~3-4 days, with the other two taking
+5-6 days on average.
 
 While crater is really useful, it is also important to be aware of a few
 caveats:
@@ -37,9 +37,9 @@ caveats:
 - Crater only runs Linux builds on x86_64. Thus, other architectures and
   platforms are not tested. Critically, this includes Windows.
 
-- Many crates are not tested. This could be for a lot of reasons, including
-  that the crate doesn't compile any more (e.g. used old nightly features),
-  has broken or flaky tests, requires network access, or other reasons.
+- Many crates are not tested. This could be for a lot of reasons, including that
+  the crate doesn't compile any more (e.g. used old nightly features), has
+  broken or flaky tests, requires network access, or other reasons.
 
 - Before crater can be run, `@bors try` needs to succeed in building artifacts.
   This means that if your code doesn't compile, you cannot run crater.