Amend the triagebot comment for Cargo.lock changes.

I don't like the current wording. It's obnoxious to be told by a bot
that a change I made intentionally is "probably unintentional"! I also
don't like describing unintentional changes as "Random", it's not the
right word.

Author: nnethercote

triagebot.toml

@@ -475,10 +475,10 @@ cc = ["@rust-lang/style"]
 
 [mentions."Cargo.lock"]
 message = """
-These commits modify the `Cargo.lock` file. Random changes to `Cargo.lock` can be introduced when switching branches and rebasing PRs.
-This was probably unintentional and should be reverted before this PR is merged.
+These commits modify the `Cargo.lock` file. Unintentional changes to `Cargo.lock` can be introduced when switching branches and rebasing PRs.
 
-If this was intentional then you can ignore this comment.
+If this was unintentional then you should revert the changes before this PR is merged.
+Otherwise, you can ignore this comment.
 """
 
 [mentions."src/tools/x"]