[F42] cargo doc --workspace --no-deps clean (0 warnings)

Fix all 33 rustdoc warnings across the workspace:

- Unresolved intra-doc links: rewrite [`name`] → either backtick text
  (when not actually a link) or fully-qualified `[Type::method]` /
  `[crate::module::name]` form. Affected: mxaccess-codec
  (asb_variant, item_control, metadata_query, observed_write_template,
  reference_handle, write_message), mxaccess-rpc (pdu), mxaccess-nmx
  (client), mxaccess-asb-nettcp (nmf), mxaccess-callback (exporter),
  mxaccess (asb_session, session, lib).
- Bracket-text being interpreted as link refs (e.g. `body[17]` →
  `` `body[17]` ``).
- Private-item references in public docs (CALLBACK_BROADCAST_CAPACITY,
  recover_connection_core, mxvalue_to_writevalue) reduced to
  backtick-text since they aren't part of the public API.

`RUSTDOCFLAGS="-D warnings" cargo doc --workspace --no-deps` now
exits clean. Workspace 759 tests pass; clippy clean.

Defers `#![warn(missing_docs)]` lint to a future pass — the cleanup
target is the broken-link warnings, which are signal; missing-docs
would surface hundreds of low-priority public-item gaps that are out
of scope for this F-number.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

rust/crates/mxaccess-rpc/src/pdu.rs

@@ -539,7 +539,7 @@ impl BindPdu {
 
     /// Encode the Bind / AlterContext PDU. Returns the wire bytes
     /// (`DceRpcPdu.cs:264-290`). Sets `frag_length` and `auth_length=0` on
-    /// the encoded header — to attach an auth verifier use [`encode_with_auth`].
+    /// the encoded header — to attach an auth verifier use [`Self::encode_with_auth`].
     pub fn encode(&self) -> Vec<u8> {
         let length: usize = BIND_BODY_OFFSET
             + self
@@ -955,7 +955,7 @@ impl BindAckPdu {
 ///
 /// The .NET `Encode` (`DceRpcPdu.cs:118-124`) defaults `packet_flags` to
 /// `0x03` (PFC_FIRST_FRAG | PFC_LAST_FRAG) only when the supplied flags are
-/// 0; the Rust port keeps the same exact behaviour in [`encode`].
+/// 0; the Rust port keeps the same exact behaviour in [`RequestPdu::encode`].
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct RequestPdu {
     pub header: PduHeader,
@@ -1081,7 +1081,7 @@ pub struct ResponsePdu {
 
 impl ResponsePdu {
     /// Decode a Response PDU (`DceRpcPdu.cs:141-168`). The .NET reference
-    /// has no encoder for Response — the Rust port adds [`encode`] for tests
+    /// has no encoder for Response — the Rust port adds [`Self::encode`] for tests
     /// and round-trip use.
     pub fn decode(buf: &[u8]) -> Result<Self, RpcError> {
         let header = PduHeader::decode(buf)?;