docs: shorten help and migration texts to gh-like brevity

Long texts no longer restate the flag list, the instance selection
of tea help environment, the config keys with descriptions or the
team argument rules shown under ARGUMENTS; webhook events come from
services.WebhookEvents; the migration guide refers to tea help
formatting for the terminal layout.

Signed-off-by: bircni <bircni@icloud.com>

internal/app/auth.go

@@ -103,7 +103,8 @@ func (a *application) authCommand() *cobra.Command {
 tea keeps the accounts of each instance in hosts.yml and their tokens in the system
 keyring, or in a private file when you choose so. One account per instance is active;
 --user or TEA_USER selects another for a single command. GITEA_TOKEN, together with
-GITEA_INSTANCE_URL or TEA_HOST, replaces the stored credentials of its instance.`}
+GITEA_INSTANCE_URL or TEA_HOST, replaces the stored credentials of its instance. See
+tea help environment for how commands select the instance.`}
 	group.AddCommand(a.loginCommand(), a.logoutCommand(), a.authStatusCommand(), a.authSwitchCommand(), a.authRefreshCommand(), a.authTokenCommand(), a.setupGitCommand(), a.gitCredentialCommand())
 	return group
 }
@@ -124,17 +125,8 @@ func (a *application) loginCommand() *cobra.Command {
 	login := &cobra.Command{
 		Use: "login", Short: "Log in to a Gitea instance", Args: argsExact(0),
 		Annotations: map[string]string{"tea.text": "login does not return a resource", "tea.confirm": "true"},
-		Long: `Log in to a Gitea instance.
-
-On a terminal without a method flag, tea asks for the instance, how to log in, where to
-keep the token and whether git should use tea for the instance. Otherwise choose one
-method:
-
-  --with-token             read an access token from stdin, or ask for it on a terminal
-  --oauth, --web           authorize tea in a web browser
-  --ssh-key FILE           sign requests with an SSH private key
-  --ssh-agent-key FP       sign requests with the key of fingerprint FP in ssh-agent
-  --ssh-agent-principal P  sign requests with the ssh-agent certificate of principal P
+		Long: `Log in to a Gitea instance. On a terminal without a method flag, tea asks for the instance,
+how to log in, where to keep the token and whether git should use tea for the instance.
 
 Create a token on the instance under Settings > Applications. Logging in to an account
 that tea already has replaces its stored credential after a confirmation (or with --yes).`,
@@ -427,11 +419,8 @@ func (a *application) authStatusCommand() *cobra.Command {
 	status := &cobra.Command{
 		Use: "status", Short: "Show the accounts tea can use", Args: argsExact(0),
 		Long: `Show the accounts tea can use on each instance, the active one, and how they
-authenticate. --verify asks each instance whether the credentials still work.
-
-A GITEA_TOKEN in the environment shows under its instance, where it replaces the stored
-accounts. tea auth status fails with exit code 4 when there is no account, or when a
-credential is missing or rejected.`,
+authenticate. Fails with exit code 4 when there is no account, or when a credential is
+missing or rejected.`,
 		Example: `$ tea auth status
 # Check the credentials against their instances
 $ tea auth status --verify
@@ -637,8 +626,7 @@ func (a *application) authSwitchCommand() *cobra.Command {
 		Annotations: textOutput("switching accounts does not return a resource"), ValidArgsFunction: a.completeAccounts,
 		Long: `Switch the active account of an instance, which commands use unless --user or TEA_USER
 selects another. With two accounts, tea auth switch toggles between them; with more, it
-asks which one on a terminal. The instance is the one of the current repository, else
---host, TEA_HOST, default_host or the only instance.`,
+asks which one on a terminal.`,
 		Example: "$ tea auth switch\n$ tea auth switch bob\n$ tea auth switch bob --host gitea.com",
 		RunE: func(cmd *cobra.Command, args []string) error {
 			t, err := a.instanceTarget(cmd.Context())
@@ -718,11 +706,7 @@ func (a *application) logoutCommand() *cobra.Command {
 		Annotations: map[string]string{"tea.text": "logout does not return a resource", "tea.confirm": "true"},
 		Long: `Log out of an account: tea forgets the account and deletes its stored credential. Git's
 other credential helpers are asked to forget what they stored for the account on the
-instance, such as a copy of its token that a keychain kept after a push.
-
-Without an account argument or --user, tea logs out of the active account of the
-current repository's instance, else of --host, TEA_HOST, default_host or the only
-instance.`,
+instance, such as a copy of its token that a keychain kept after a push.`,
 		Example: "$ tea auth logout\n$ tea auth logout bob --host gitea.com\n# Without confirmation\n$ tea auth logout alice --yes",
 		RunE: func(cmd *cobra.Command, args []string) error {
 			if len(args) == 1 {