fix: make IpcMessage members non-public (#366)

The original `OpaqueIpcMessage` struct that was superseded by the new
`IpcMessage` had only non-public members, Having the members of
`IpcMessage` marked as `pub` also mean they become part of the API,
which we don't expect to be useful. So this change just marks them as
`pub(crate)`.

Signed-off-by: Mukilan Thiyagarajan <[email protected]>

Author: mukilan

src/ipc.rs

@@ -665,9 +665,9 @@ impl IpcSelectionResult {
 /// [to]: #method.to
 #[derive(PartialEq)]
 pub struct IpcMessage {
-    pub data: Vec<u8>,
-    pub os_ipc_channels: Vec<OsOpaqueIpcChannel>,
-    pub os_ipc_shared_memory_regions: Vec<OsIpcSharedMemory>,
+    pub(crate) data: Vec<u8>,
+    pub(crate) os_ipc_channels: Vec<OsOpaqueIpcChannel>,
+    pub(crate) os_ipc_shared_memory_regions: Vec<OsIpcSharedMemory>,
 }
 
 impl IpcMessage {