Rollup merge of #63077 - petrochenkov:nolangfeat, r=petrochenkov

cleanup: Remove some language features related to built-in macros

They are now library features.
Cleanup after #62086.
The unstable book files are moved because tidy complained.

Author: Centril

src/doc/unstable-book/src/language-features/asm.md renamed to src/doc/unstable-book/src/library-features/asm.md

@@ -243,9 +243,6 @@ declare_features! (
     // Allows using `#![needs_allocator]`, an implementation detail of `#[global_allocator]`.
     (active, allocator_internals, "1.20.0", None, None),
 
-    // Allows using the `format_args_nl` macro.
-    (active, format_args_nl, "1.29.0", Some(0), None),
-
     // no-tracking-issue-end
 
     // Added for testing E0705; perma-unstable.
@@ -286,12 +283,6 @@ declare_features! (
     // feature-group-start: actual feature gates
     // -------------------------------------------------------------------------
 
-    // Allows using `asm!` macro with which inline assembly can be embedded.
-    (active, asm, "1.0.0", Some(29722), None),
-
-    // Allows using the `concat_idents!` macro with which identifiers can be concatenated.
-    (active, concat_idents, "1.0.0", Some(29599), None),
-
     // Allows using the `#[link_args]` attribute.
     (active, link_args, "1.0.0", Some(29596), None),
 
@@ -307,12 +298,6 @@ declare_features! (
     // Allows using `#[thread_local]` on `static` items.
     (active, thread_local, "1.0.0", Some(29594), None),
 
-    // Allows using the `log_syntax!` macro.
-    (active, log_syntax, "1.0.0", Some(29598), None),
-
-    // Allows using the `trace_macros!` macro.
-    (active, trace_macros, "1.0.0", Some(29598), None),
-
     // Allows the use of SIMD types in functions declared in `extern` blocks.
     (active, simd_ffi, "1.0.0", Some(27731), None),
 
@@ -402,9 +387,6 @@ declare_features! (
     // Allows `extern "x86-interrupt" fn()`.
     (active, abi_x86_interrupt, "1.17.0", Some(40180), None),
 
-    // Allows module-level inline assembly by way of `global_asm!()`.
-    (active, global_asm, "1.18.0", Some(35119), None),
-
     // Allows overlapping impls of marker traits.
     (active, overlapping_marker_traits, "1.18.0", Some(29864), None),
 

src/doc/unstable-book/src/language-features/concat-idents.md renamed to src/doc/unstable-book/src/library-features/concat-idents.md

@@ -1,4 +1,3 @@
-// gate-test-asm
 // ignore-emscripten
 
 fn main() {

src/doc/unstable-book/src/language-features/global-asm.md renamed to src/doc/unstable-book/src/library-features/global-asm.md

@@ -1,5 +1,5 @@
 error[E0658]: use of unstable library feature 'asm': inline assembly is not stable enough for use and is subject to change
-  --> $DIR/feature-gate-asm2.rs:6:26
+  --> $DIR/feature-gate-asm2.rs:5:26
    |
 LL |         println!("{:?}", asm!(""));
    |                          ^^^

src/doc/unstable-book/src/language-features/trace-macros.md renamed to src/doc/unstable-book/src/library-features/trace-macros.md

@@ -1,5 +1,3 @@
-// gate-test-concat_idents
-
 fn main() {
     concat_idents!(a, b); //~ ERROR `concat_idents` is not stable enough
                           //~| ERROR cannot find value `ab` in this scope

src/libsyntax/feature_gate.rs

@@ -1,5 +1,5 @@
 error[E0658]: use of unstable library feature 'concat_idents': `concat_idents` is not stable enough for use and is subject to change
-  --> $DIR/feature-gate-concat_idents2.rs:4:5
+  --> $DIR/feature-gate-concat_idents2.rs:2:5
    |
 LL |     concat_idents!(a, b);
    |     ^^^^^^^^^^^^^
@@ -8,7 +8,7 @@ LL |     concat_idents!(a, b);
    = help: add `#![feature(concat_idents)]` to the crate attributes to enable
 
 error[E0425]: cannot find value `ab` in this scope
-  --> $DIR/feature-gate-concat_idents2.rs:4:5
+  --> $DIR/feature-gate-concat_idents2.rs:2:5
    |
 LL |     concat_idents!(a, b);
    |     ^^^^^^^^^^^^^^^^^^^^^ not found in this scope

src/test/ui/feature-gates/feature-gate-asm2.rs

@@ -1,5 +1,3 @@
-// gate-test-concat_idents
-
 const XY_1: i32 = 10;
 
 fn main() {