block: Rename AsyncDiskFile::new_async_io to create_async_io

The new_ prefix in Rust conventionally denotes constructors that return
Self (e.g. Vec::new(), File::new()). AsyncDiskFile::new_async_io does
not return Self. It is a factory method that constructs and returns a
Box<dyn AsyncIo> worker bound to the disk file descriptor and
metadata. The create_ prefix communicates this: the caller receives
a freshly constructed object of a different type.

This rename touches every format backend in block plus two external
callers in virtio-devices and performance-metrics. Every change is a
mechanical s/new_async_io/create_async_io/ substitution. No functional
change.

Ref: #7877 (task 3.2.8)
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>

block/src/async_io.rs

@@ -72,7 +72,7 @@ pub trait DiskFile: Send {
     fn logical_size(&mut self) -> DiskFileResult<u64>;
     /// Returns the physical size of the underlying file.
     fn physical_size(&mut self) -> DiskFileResult<u64>;
-    fn new_async_io(&self, ring_depth: u32) -> DiskFileResult<Box<dyn AsyncIo>>;
+    fn create_async_io(&self, ring_depth: u32) -> DiskFileResult<Box<dyn AsyncIo>>;
     fn topology(&mut self) -> DiskTopology {
         DiskTopology::default()
     }