Update src/std_misc/file/read_lines.md

Co-authored-by: Samuel Eisenhandler <[email protected]>

Author: pringshia

src/std_misc/file/read_lines.md

@@ -41,7 +41,7 @@ and `String::from` respectively.
 
 ## A more efficient approach
 
-Here we use the `BufRead` class to read the file. `BufRead` uses an internal
+Here we pass ownership of the open `File` to a `BufReader` struct. `BufReader` uses an internal
 buffer to reduce intermediate allocations.
 
 We also update `read_lines` to return an iterator instead of allocating new