btrfs: documented Chunk class (no functional change)

Change-Id: I9f1c47728297d7e29033beed7338bbd44d6d13cd
Reviewed-on: https://review.haiku-os.org/c/haiku/+/1492
Reviewed-by: Adrien Destugues <[email protected]>
Reviewed-by: Chế Vũ Gia Hy <[email protected]>

src/add-ons/kernel/file_systems/btrfs/Chunk.h

@@ -13,12 +13,15 @@
 #include "btrfs.h"
 
 
+//! Used to translate logical addresses to physical addresses
 class Chunk {
 public:
 								Chunk(btrfs_chunk* chunk,
 									fsblock_t offset);
 								~Chunk();
+			//! \return Value of current physical size
 			uint32				Size() const;
+			//! Used to convert logical addresses into physical addresses
 			status_t			FindBlock(off_t logical, off_t& physical);
 			fsblock_t			Offset() const { return fChunkOffset; }
 			fsblock_t			End() const