Remove Doxygen-style comments, change formatting to wrap comments

kernel/amd64/gdt.h

@@ -11,13 +11,11 @@
 #define GDT_UDATA 0x20
 #define GDT_TSS   0x28
 
-/// Size of kernel stack
+/* Size of kernel stack */
 #define KSTACK_SIZE (32 * 1024)
 
-/**
- * @file
- *
- * @brief 64-bit GDT structure. For more info see:
+/*
+ * 64-bit GDT structure. For more info see:
  * - https://wiki.osdev.org/Global_Descriptor_Table
  * - https://wiki.osdev.org/GDT_Tutorial
  */
@@ -31,11 +29,13 @@ struct gdt_entry {
   uint8_t basehigh;
 } PACKED;
 
+/* Struct that gets loaded into GDTR */
 struct gdt_ptr {
   uint16_t limit;
   uint64_t base;
 } PACKED;
 
+/* New, extended GDT (we need to extend Limine's GDT) */
 struct gdt_extended {
   struct gdt_entry old[5];
   struct gdt_entry tsslow;