Auto merge of #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

library/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)]