Clarify Return to Game Mode switch help (#158)

Co-authored-by: SAPHID <saphid@users.noreply.github.com>

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+- Correct the Return to Game Mode help text: Frame Control selects the switch
+  supported by the headset's SteamOS build, including `steamosctl` on current
+  Frames. The button's behavior is unchanged.
+
 - Distinguish an unreadable gamescope panel list from a confirmed empty list in
   Desktop Capture and Control (issue #73). Failed discovery now asks users to
   check SteamVR and report the exact message and SteamOS version, rather than

ui/index.html

@@ -1738,7 +1738,7 @@
         <button class="small" id="sessionCheck">Check</button></div>
       <div class="sub" id="sessionState">Check which mode the headset is in.</div>
       <div class="row" style="margin-top:12px"><button class="small" id="sessionGame" disabled>Return to Game Mode</button></div>
-      <div class="hint">Uses the same switch as Valve's developer tools (<code>steamos-session-select gamescope</code>).
+      <div class="hint">Uses Valve's supported Game Mode switch for this SteamOS build.
         It closes the desktop and anything open in it. If the headset can't be reached, hold Power for 10 seconds to
         restart it; <a href="https://github.com/saphid/frame-control/blob/main/docs/backup-and-recovery.md#stuck-in-desktop-mode" target="_blank">more ways back</a>.</div>
     </section>