A few documentation updates

src/kernel/synch.rs

@@ -43,12 +43,12 @@ impl Semaphore {
         machine.interrupt.set_status(old_status);
     }
 
-    ///      Increment semaphore value, waking up a waiting thread if any.
+    /// Increment semaphore value, waking up a waiting thread if any.
-    ///	As with P(), this operation must be atomic, so we need to disable
+    /// As with P(), this operation must be atomic, so we need to disable
-    ///	interrupts.
+    /// interrupts.
     ///
     /// scheduler::ready_to_run() assumes that interrupts
-    ///	are disabled when it is called.
+    /// are disabled when it is called.
     ///
     /// ### Parameters
     /// - **machine** the machine where the threads are executed

src/kernel/thread_manager.rs

@@ -6,17 +6,26 @@ use super::{scheduler::Scheduler, thread::Thread, system::System, mgerror::Error
 
 pub const SIMULATORSTACKSIZE: usize = 32 * 1024;
 
+/// # Thread manager
+/// 
+/// An instance of this struct is responsible for managing threads on behalf of the system
 #[derive(PartialEq)]
 pub struct ThreadManager {
+    /// Current running thread
     pub g_current_thread: Option<Rc<RefCell<Thread>>>,
+    /// The thread to be destroyed next
     pub g_thread_to_be_destroyed: Option<Rc<RefCell<Thread>>>,
+    /// The list of alive threads
     pub g_alive: List<Rc<RefCell<Thread>>>,
+    /// The thread scheduler
     pub g_scheduler: Scheduler,
+    /// The system owning the thread manager
     pub system: Option<Rc<RefCell<System>>>
 }
 
 impl ThreadManager {
 
+    /// Thread manager constructor
     pub fn new() -> Self {
         Self { 
             g_current_thread: Option::None,