fix: display force-tty flag (#17067)

Fixes: https://github.com/coder/coder/issues/17033

cli/root.go

@@ -433,7 +433,7 @@ func (r *RootCmd) Command(subcommands []*serpent.Command) (*serpent.Command, err
 		{
 			Flag:        varForceTty,
 			Env:         "CODER_FORCE_TTY",
-			Hidden:      true,
+			Hidden:      false,
 			Description: "Force the use of a TTY.",
 			Value:       serpent.BoolOf(&r.forceTTY),
 			Group:       globalGroup,

cli/testdata/coder_--help.golden

@@ -79,6 +79,9 @@ variables or flags.
           Coder. Network telemetry is used to measure network quality and detect
           regressions.
 
+      --force-tty bool, $CODER_FORCE_TTY
+          Force the use of a TTY.
+
       --global-config string, $CODER_CONFIG_DIR (default: ~/.config/coderv2)
           Path to the global `coder` config directory.