block: Remove qcow compat alias

Update external consumers to use formats::qcow::internal instead
of the top level qcow alias. Keep a crate private use for the
QcowError variant in lib.rs.

Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>

block/src/formats/qcow/internal/mod.rs

@@ -664,7 +664,7 @@ pub(crate) fn parse_qcow(
 /// # Example
 ///
 /// ```
-/// # use block::qcow::{self, QcowFile, RawFile};
+/// # use block::formats::qcow::internal::{QcowFile, RawFile};
 /// # use std::io::{Read, Seek, SeekFrom};
 /// # fn test(file: std::fs::File) -> std::io::Result<()> {
 ///     let mut raw_img = RawFile::new(file, false);

block/src/lib.rs

@@ -27,7 +27,7 @@ use std::path::Path;
 use std::str::FromStr;
 use std::{cmp, mem, result};
 
-pub use formats::qcow::internal as qcow;
+use formats::qcow::internal as qcow;
 pub use formats::vhdx::internal as vhdx;
 #[cfg(feature = "io_uring")]
 use io_uring::{IoUring, Probe, opcode};