add more details about shortcuts

Author: chenyukang

src/rustbot.md

@@ -44,9 +44,12 @@ the `@rustbot` command will look like this:
     @rustbot label -S-waiting-on-author +S-waiting-on-review
 
 The syntax for this command is pretty loose, so there are other variants of this
-command invocation. For more details, see [the docs page about labeling][labeling].
+command invocation. There are also some shortcuts to update labels,
+for instance `@rustbot ready` will do the same thing with above command.
+For more details, see [the docs page about labeling][labeling] and [shortcuts][shortcuts].
 
 [labeling]: https://forge.rust-lang.org/triagebot/labeling.html
+[shortcuts]: https://forge.rust-lang.org/triagebot/shortcuts.html
 
 ## Other commands
 

src/walkthrough.md

@@ -196,7 +196,8 @@ Feel free to ask questions or discuss things you don't understand or disagree wi
 recognize that the PR won't be merged unless someone on the Rust team approves
 it. If a reviewer leave a comment like `r=me after fixing ...`, that means they approve the PR and 
 you can merge it with comment with `@bors r=reviwer-github-id`(e.g. `@bors r=eddyb`) to merge it 
-after fixing lefted trivial issues.
+after fixing lefted trivial issues. `r=someone` requires permission and the reviwer use
+delegate command gives it to you in this way.
 
 When your reviewer approves the PR, it will go into a queue for yet another bot
 called `@bors`. `@bors` manages the CI build/merge queue. When your PR reaches