feat: HDMI refresh boost and Update BIOS under Steam Machine support

Both are sub-options of Steam Machine support now, shown only while it is
ticked. Unticking it unticks them; unticking the kernel pin unticks the
HDMI refresh boost, which only works with the pinned kernel.

README.md

@@ -50,15 +50,15 @@ What Steamify can do on a Valve Steam Machine:
     [release](https://github.com/theupriser/steamify-cachyos/releases/tag/kernel-7.1.6-1),
     checked against CachyOS's signature
     ([details](TECHNICAL.md#kernel-pin-steam-machine)).
-- **HDMI refresh boost** - only with the pinned kernel, never ticked by
-  default: gets the highest refresh rate your HDMI display runs at the
-  desktop resolution (e.g. 110 Hz instead of 60 on a 3440x1440 monitor).
-  Each step is shown and you confirm it; no answer within 15 s switches
-  back. For more (e.g. 175 Hz), use DisplayPort
-  ([details](TECHNICAL.md#hdmi-refresh-boost-steam-machine)).
-- **Update BIOS** - installs Valve's newest Steam Machine BIOS. Never ticked
-  by default, at your own risk, and only after two warnings
-  ([details](TECHNICAL.md#bios-updates-steam-machine)).
+  - **HDMI refresh boost** - only with the pinned kernel, never ticked by
+    default: gets the highest refresh rate your HDMI display runs at the
+    desktop resolution (e.g. 110 Hz instead of 60 on a 3440x1440 monitor).
+    Each step is shown and you confirm it; no answer within 15 s switches
+    back. For more (e.g. 175 Hz), use DisplayPort
+    ([details](TECHNICAL.md#hdmi-refresh-boost-steam-machine)).
+  - **Update BIOS** - installs Valve's newest Steam Machine BIOS. Never ticked
+    by default, at your own risk, and only after two warnings
+    ([details](TECHNICAL.md#bios-updates-steam-machine)).
 
 ## Requirements