gt: update more information and more commands (#15596)

pages/common/gt.md

@@ -1,28 +1,32 @@
 # gt
 
 > Create and manage sequences of dependent code changes (stacks) for Git and GitHub.
-> More information: <https://docs.graphite.dev>.
-
-- Authenticate the CLI with Graphite's API:
-
-`gt auth --token {{graphite_cli_auth_token}}`
+> More information: <https://graphite.dev/docs/get-started>.
 
 - Initialise `gt` for the repository in the current directory:
 
-`gt repo init`
+`gt init`
 
 - Create a new branch stacked on top of the current branch and commit staged changes:
 
-`gt branch create {{branch_name}}`
+`gt create {{branch_name}}`
 
 - Create a new commit and fix upstack branches:
 
-`gt commit create -m {{commit_message}}`
+`gt modify -cam {{commit_message}}`
 
 - Force push all branches in the current stack to GitHub and create or update PRs:
 
 `gt stack submit`
 
+- Checkout different branch (prompts interactive mode when branch name is omitted):
+
+`gt co {{branch_name}}`
+
+- Sync stack with remote version (also deletes merged branches):
+
+`gt sync`
+
 - Log all tracked stacks:
 
 `gt log short`