Merge pull request #2831 from reddevilmidzy/bors-squash

Document quoting for `@bors squash msg=`

Author: reddevilmidzy

src/git.md

@@ -386,7 +386,8 @@ the history becomes easier to work with.
 The easiest way to squash your commits in a PR on the `rust-lang/rust` repository is to use the `@bors squash` command in a comment on the PR.
 By default, [bors] combines all commit messages of the PR into the squashed commit message.
 To customize the commit message, use `@bors squash msg=<commit message>`.
-
+If you want to use multiple words in the commit message, wrap it in double quotes.
+For example, `@bors squash msg="Improve diagnostics for missing lifetime parameter"`.
 
 If you want to squash commits using local git operations, read on below.