docs: Drop the kernel pin and HDMI refresh boost descriptions

README.md

@@ -48,16 +48,6 @@ What Steamify can do on a Valve Steam Machine:
   - **Power-off fix** - on by default: shutting down really turns the Steam
     Machine off, also with the newest CachyOS kernel
     ([details](TECHNICAL.md#power-off-fix-steam-machine)).
-  - **Pin the kernel to 7.1.6-1** - no longer offered: it was needed for
-    shutting down, which the power-off fix above covers now. An existing pin
-    is shown unticked, so the next run removes it and brings back CachyOS's
-    current kernel ([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)).