refactor(userspace): split syscall/fat16/ext4 by concern; trim comments

crates/init/src/devices.rs

@@ -1,7 +1,5 @@
-//! Which driver gets which device. Boot gave init a capability to every
-//! board device and a page saying where they are (`types::bootinfo`); init
-//! asks each virtio slot what it is and hands the disk, the GPU and the
-//! keyboard (or, without one, the UART) to their drivers.
+//! Finds the board's devices (`types::bootinfo`): disk, GPU, and keyboard
+//! (or the UART when there is none).
 
 use hw_virtio::mmio::{
     DEVICE_ID_BLOCK, DEVICE_ID_GPU, DEVICE_ID_INPUT, MAGIC, REG_DEVICE_ID, REG_MAGIC,
@@ -84,7 +82,7 @@ pub fn discover() -> Devices {
             },
             _ => continue,
         };
-        // The first device of each kind wins.
+        // First device of each kind wins.
         if place.mmio.is_none() {
             *place = dev;
         }