error: hide struct Error into error module

That matches code convention in `serde-json` crate: https://docs.rs/serde_json/latest/serde_json/index.html
which does not expose error::Error type into crate root.

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

Author: luojia65

examples/qemu-virt.rs

@@ -12,7 +12,7 @@ use serde_derive::Deserialize;
 // - `StrSeq`: '\0' 分隔的一组字符串，设备树中一种常见的属性类型，这个类型要求可变的内存。
 use serde_device_tree::{
     buildin::{NodeSeq, Reg, StrSeq},
-    from_raw_mut, Dtb, DtbPtr, Error,
+    from_raw_mut, Dtb, DtbPtr, error::Error,
 };
 
 fn main() -> Result<(), Error> {

src/common.rs

@@ -1,4 +1,4 @@
-use crate::Error;
+use crate::error::Error;
 
 #[derive(Debug, Clone)]
 #[repr(C)]

src/de_mut/mod.rs

@@ -1,7 +1,7 @@
 //! Deserialize device tree data to a Rust data structure,
 //! the memory region contains dtb file should be mutable.
 
-use crate::Error as DtError;
+use crate::error::Error as DtError;
 use serde::de;
 
 mod cursor;

src/de_mut/structs.rs

@@ -1,6 +1,6 @@
 use crate::{
     common::{Header, ALIGN},
-    Error as DtError,
+    error::Error as DtError,
 };
 use core::{cell::RefCell, fmt::Display};
 

src/lib.rs

@@ -31,4 +31,4 @@ pub use de::from_raw;
 pub use de_mut::{buildin, from_raw_mut, Dtb, DtbPtr};
 
 #[doc(inline)]
-pub use error::{Error, Result};
+pub use error::Result;