CLEANUP: Fix typos in the file descriptor subsystem

Fixes 2 typos in the code comment of the file descriptor subsystem.
diff --git a/include/types/fd.h b/include/types/fd.h
index 5947baf..3ff4f65 100644
--- a/include/types/fd.h
+++ b/include/types/fd.h
@@ -80,8 +80,8 @@
 
 /* This is the value used to mark a file descriptor as dead. This value is
  * negative, this is important so that tests on fd < 0 properly match. It
- * also has the nice property of being highly negative but not overflowing
- * nor changing sign on 32-bit machines when multipled by sizeof(fdtab).
+ * also has the nice property of being highly negative but neither overflowing
+ * nor changing sign on 32-bit machines when multiplied by sizeof(fdtab).
  * This ensures that any unexpected dereference of such an uninitialized
  * file descriptor will lead to so large a dereference that it will crash
  * the process at the exact location of the bug with a clean stack trace