update readme

README.md

@@ -19,7 +19,9 @@ use strafesnet_roblox_bot_file::v0::{Block,BlockTimelines,FileHeader};
 let file=std::fs::read("bot_file")?;
 let mut input=std::io::Cursor::new(file);
 
+// FileHeader is the first 16 bytes of the file.
 let header=FileHeader::from_reader(&mut input)?;
+// BlockTimelines is an index of the blocks within the file.
 let timelines=BlockTimelines::from_reader(&header,&mut input)?;
 
 // offline blocks include the following event types: