Rollup merge of rust-lang#94957 - iamzhangyong:explanation-read_line, r=Dylan-DPC

Dylan-DPC · web-flow · commit 0732ea2f3ed2 · 2022-03-16T03:34:34.000+01:00
Improve the explanation about the behaviour of read_line Close issue like rust-lang/book#2574
diff --git a/library/std/src/io/mod.rs b/library/std/src/io/mod.rs
@@ -2110,7 +2110,8 @@ pub trait BufRead: Read {
     }
 
     /// Read all bytes until a newline (the `0xA` byte) is reached, and append
-    /// them to the provided buffer.
+    /// them to the provided buffer. You do not need to clear the buffer before
+    /// appending.
     ///
     /// This function will read bytes from the underlying stream until the
     /// newline delimiter (the `0xA` byte) or EOF is found. Once found, all bytes

Original file line number	Diff line number	Diff line change
`@@ -2110,7 +2110,8 @@ pub trait BufRead: Read {`
`2110`	`2110`	`}`
`2111`	`2111`
`2112`	`2112`	/// Read all bytes until a newline (the `0xA` byte) is reached, and append
`2113`		`- /// them to the provided buffer.`
	`2113`	`+ /// them to the provided buffer. You do not need to clear the buffer before`
	`2114`	`+ /// appending.`
`2114`	`2115`	`///`
`2115`	`2116`	`/// This function will read bytes from the underlying stream until the`
`2116`	`2117`	/// newline delimiter (the `0xA` byte) or EOF is found. Once found, all bytes