Use doc_cfg instead of doc_auto_cfg (#411)

#### Problem

The docs builds are currently failing due to the changes in
<rust-lang/rust#138907>.

#### Summary of changes

As recommended there, use `doc_cfg` instead of `doc_auto_cfg`.

Author: joncinque

account-info/src/lib.rs

@@ -1,5 +1,5 @@
 //! Account information.
-#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 use {
     solana_address::Address,
     solana_program_error::ProgramError,

account-view/src/lib.rs

@@ -1,7 +1,7 @@
 //! Data structures to represent account information.
 
 #![no_std]
-#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 #![allow(clippy::arithmetic_side_effects)]
 
 use {

account/src/lib.rs

@@ -1,5 +1,5 @@
 #![cfg_attr(feature = "frozen-abi", feature(min_specialization))]
-#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 //! The Solana [`Account`] type.
 
 #[cfg(feature = "dev-context-only-utils")]

address-lookup-table-interface/src/lib.rs

@@ -1,5 +1,5 @@
 #![cfg_attr(feature = "frozen-abi", feature(min_specialization))]
-#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 //! The [address lookup table program][np].
 //!
 //! [np]: https://docs.solanalabs.com/runtime/programs#address-lookup-table-program

address/src/lib.rs

@@ -4,7 +4,7 @@
 //! (e.g. 14grJpemFaf88c8tiVb77W7TYg2W3ir6pfkKz3YjhhZ5).
 
 #![no_std]
-#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 #![cfg_attr(feature = "frozen-abi", feature(min_specialization))]
 #![allow(clippy::arithmetic_side_effects)]
 

atomic-u64/src/lib.rs

@@ -1,5 +1,5 @@
 #![no_std]
-#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 pub use implementation::AtomicU64;
 
 #[cfg(target_pointer_width = "64")]

big-mod-exp/src/lib.rs

@@ -1,4 +1,4 @@
-#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 #[repr(C)]
 pub struct BigModExpParams {
     pub base: *const u8,

bincode/src/lib.rs

@@ -1,7 +1,7 @@
 //! Contains a single utility function for deserializing from [bincode].
 //!
 //! [bincode]: https://docs.rs/bincode
-#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 
 use {bincode::config::Options, solana_instruction_error::InstructionError};
 

blake3-hasher/src/lib.rs

@@ -2,7 +2,7 @@
 //!
 //! [blake3]: https://github.com/BLAKE3-team/BLAKE3
 #![no_std]
-#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 
 pub use solana_hash::{Hash, ParseHashError, HASH_BYTES, MAX_BASE58_LEN};
 

bls-signatures/src/lib.rs

@@ -1,5 +1,5 @@
 #![no_std]
-#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 #![cfg_attr(feature = "frozen-abi", feature(min_specialization))]
 
 extern crate alloc;