docs(hal): Fix broken intra-doc links

Replace problematic intra-doc links with code formatting
to resolve rustdoc warnings in digest and i2c_device modules.

Author: rusty1968

hal/blocking/src/digest.rs

@@ -25,17 +25,17 @@
 //!
 //! ## Key Components
 //!
-//! - [`Digest`] - A generic container for digest output values
-//! - [`DigestAlgorithm`] - Trait defining digest algorithm properties
+//! - `Digest` - A generic container for digest output values
+//! - `DigestAlgorithm` - Trait defining digest algorithm properties
 //!
 //! ### Scoped API
-//! - [`scoped::DigestInit`] - Trait for initializing digest operations (borrowed contexts)
-//! - [`scoped::DigestOp`] - Trait for performing digest computations (borrowed contexts)
-//! - [`scoped::DigestCtrlReset`] - Trait for resetting digest contexts
+//! - `scoped::DigestInit` - Trait for initializing digest operations (borrowed contexts)
+//! - `scoped::DigestOp` - Trait for performing digest computations (borrowed contexts)
+//! - `scoped::DigestCtrlReset` - Trait for resetting digest contexts
 //!
 //! ### Owned API (Typestate)
-//! - [`owned::DigestInit`] - Trait for initializing digest operations (owned contexts)
-//! - [`owned::DigestOp`] - Trait for performing digest computations (owned contexts)
+//! - `owned::DigestInit` - Trait for initializing digest operations (owned contexts)
+//! - `owned::DigestOp` - Trait for performing digest computations (owned contexts)
 //!
 //! ## Supported Algorithms
 //!

hal/blocking/src/i2c_device.rs

@@ -90,12 +90,12 @@
 //!
 //! The traits are organized in a composable hierarchy:
 //!
-//! - [`I2CCoreTarget`]: Core transaction lifecycle (required for all devices)
-//! - [`WriteTarget`]: Handle write operations from master
-//! - [`ReadTarget`]: Handle read operations from master  
-//! - [`WriteReadTarget`]: Handle combined write-read transactions
-//! - [`RegisterAccess`]: Higher-level register-based access patterns
-//! - [`I2CTarget`]: Convenience trait combining all capabilities
+//! - `I2CCoreTarget`: Core transaction lifecycle (required for all devices)
+//! - `WriteTarget`: Handle write operations from master
+//! - `ReadTarget`: Handle read operations from master  
+//! - `WriteReadTarget`: Handle combined write-read transactions
+//! - `RegisterAccess`: Higher-level register-based access patterns
+//! - `I2CTarget`: Convenience trait combining all capabilities
 //!
 //! ## Transaction Flow
 //!