lib: prepare for release version 0.4.0

Remove unintended new line after document comments

Signed-off-by: Zhouqi Jiang <luojia@hust.edu.cn>

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "rustsbi"
 description = "Minimal RISC-V's SBI implementation library in Rust"
-version = "0.4.0-alpha.3"
+version = "0.4.0"
 authors = [
     "Luo Jia <me@luojia.cc>",
     "Campbell He <hkp18@mails.tsinghua.edu.cn>",

src/nacl.rs

@@ -22,7 +22,6 @@ use spec::{
 /// *NOTE:* The M-mode firmware should not implement the SBI nested acceleration
 /// extension if the underlying platform has the RISC-V H-extension implemented
 /// in hardware.
-
 pub trait Nacl {
     /// Probe nested acceleration feature.
     ///

src/sta.rs

@@ -13,7 +13,6 @@ use sbi_spec::binary::{SbiRet, SharedPtr};
 /// as steal-time accounting. The Steal-time Accounting (STA) extension defines the
 /// mechanism in which an SBI implementation provides steal-time and preemption
 /// information, for each virtual hart, to supervisor-mode software.
-
 pub trait Sta {
     /// Set Steal-time Shared Memory Address.
     ///