Auto merge of rust-lang#102919 - luojia65:update-stdarch, r=Amanieu

library: update stdarch submodule

It has been one month since we update `stdarch`  submodule into main branch Rust, it includes various fixes in code and more neat documents. This pull request also adds missing features to ensure we can build latest stdarch submodule.

The documents after this pull request:
<details>

![图片](https://user-images.githubusercontent.com/40385009/195123337-a6c4cfaa-a7b9-4574-b524-c43683e6540c.png)
</details>

Comparing to current nightly:
<details>

![图片](https://user-images.githubusercontent.com/40385009/195123430-e047cff1-a925-4d2d-ae1c-da9769383a9c.png)
</details>

r? `@Amanieu`

Author: bors

core/src/lib.rs

@@ -210,6 +210,7 @@
 #![feature(simd_ffi)]
 #![feature(staged_api)]
 #![feature(stmt_expr_attributes)]
+#![feature(target_feature_11)]
 #![feature(trait_alias)]
 #![feature(transparent_unions)]
 #![feature(try_blocks)]
@@ -225,6 +226,7 @@
 #![feature(hexagon_target_feature)]
 #![feature(mips_target_feature)]
 #![feature(powerpc_target_feature)]
+#![feature(riscv_target_feature)]
 #![feature(rtm_target_feature)]
 #![feature(sse4a_target_feature)]
 #![feature(tbm_target_feature)]

stdarch

@@ -1 +1 @@
-Subproject commit 699c093a42283c07e9763b4c19439a900ae2d321
+Subproject commit 790411f93c4b5eada3c23abb4c9a063fb0b24d99