Auto merge of #71410 - JohnTitor:rollup-vh6dut5, r=JohnTitor

Rollup of 7 pull requests

Successful merges:

 - #70998 (Suggest `-> impl Trait` and `-> Box<dyn Trait>` on fn that doesn't return)
 - #71236 (Remove unused rustc_serialize::hex module)
 - #71366 (Use assoc int consts3)
 - #71372 (Fix #! (shebang) stripping account space issue)
 - #71384 (Fix stage0.txt version number comment)
 - #71390 (Fix incorrect description of E0690)
 - #71399 (Clean up E0554 explanation)

Failed merges:

r? @ghost

3 files changed, 3 insertions, 4 deletions

diff --git a/src/librustc_error_codes/error_codes/E0554.md b/src/librustc_error_codes/error_codes/E0554.md
index e25212983eb..e55fa4c6ede 100644
--- a/src/librustc_error_codes/error_codes/E0554.md
+++ b/src/librustc_error_codes/error_codes/E0554.md
@@ -1,7 +1,7 @@
 Feature attributes are only allowed on the nightly release channel. Stable or
 beta compilers will not comply.
 
-Example of erroneous code (on a stable compiler):
+Erroneous code example:
 
 ```ignore (depends on release channel)
 #![feature(non_ascii_idents)] // error: `#![feature]` may not be used on the
diff --git a/src/librustc_error_codes/error_codes/E0690.md b/src/librustc_error_codes/error_codes/E0690.md
index 3a4d1c56fad..1673456580a 100644
--- a/src/librustc_error_codes/error_codes/E0690.md
+++ b/src/librustc_error_codes/error_codes/E0690.md
@@ -14,7 +14,7 @@ struct LengthWithUnit<U> { // error: transparent struct needs exactly one
 Because transparent structs are represented exactly like one of their fields at
 run time, said field must be uniquely determined. If there is no field, or if
 there are multiple fields, it is not clear how the struct should be represented.
-Note that fields of zero-typed types (e.g., `PhantomData`) can also exist
+Note that fields of zero-sized types (e.g., `PhantomData`) can also exist
 alongside the field that contains the actual data, they do not count for this
 error. When generic types are involved (as in the above example), an error is
 reported because the type parameter could be non-zero-sized.
diff --git a/src/librustc_error_codes/error_codes/E0746.md b/src/librustc_error_codes/error_codes/E0746.md
index 16b2722f0ea..305667e58f8 100644
--- a/src/librustc_error_codes/error_codes/E0746.md
+++ b/src/librustc_error_codes/error_codes/E0746.md
@@ -2,8 +2,7 @@ Return types cannot be `dyn Trait`s as they must be `Sized`.
 
 Erroneous code example:
 
-```compile_fail,E0277
-# // FIXME: after E0746 is in beta, change the above
+```compile_fail,E0746
 trait T {
     fn bar(&self);
 }