Update some wording making reference to issues/RFCs

Author: JohnTitor

src/exotic-sizes.md

@@ -172,10 +172,10 @@ of UB.
 There is [an accepted RFC][extern-types] to add proper types with an unknown size,
 called *extern types*, which would let Rust developers model things like C's `void*`
 and other "declared but never defined" types more accurately. However as of
-Rust 2018, the feature is stuck in limbo over how `size_of::<MyExternType>()`
-should behave.
+Rust 2018, [the feature is stuck in limbo over how `size_of_val::<MyExternType>()`
+should behave][extern-types-issue].
 
-[dst-issue]: https://github.com/rust-lang/rust/issues/26403
 [extern-types]: https://github.com/rust-lang/rfcs/blob/master/text/1861-extern-types.md
+[extern-types-issue]: https://github.com/rust-lang/rust/issues/43467
 [`str`]: ../std/primitive.str.html
 [slice]: ../std/primitive.slice.html

src/other-reprs.md

@@ -15,7 +15,7 @@ reinterpreting values as a different type.
 We strongly recommend using [rust-bindgen][] and/or [cbindgen][] to manage your FFI
 boundaries for you. The Rust team works closely with those projects to ensure
 that they work robustly and are compatible with current and future guarantees
-about type layouts and reprs.
+about type layouts and `repr`s.
 
 The interaction of `repr(C)` with Rust's more exotic data layout features must be
 kept in mind. Due to its dual purpose as "for FFI" and "for layout control",
@@ -92,7 +92,7 @@ manipulate its tag and fields. See [the RFC][really-tagged] for details.
 Adding an explicit `repr` to an enum suppresses the null-pointer
 optimization.
 
-These reprs have no effect on a struct.
+These `repr`s have no effect on a struct.
 
 ## repr(packed)
 
@@ -107,7 +107,8 @@ compiler might be able to paper over alignment issues with shifts and masks.
 However if you take a reference to a packed field, it's unlikely that the
 compiler will be able to emit code to avoid an unaligned load.
 
-**[As of Rust 2018, this still can cause undefined behavior.][ub loads]**
+[As this can cause undefined behavior][ub loads], the lint has been implemented
+and it will become a hard error.
 
 `repr(packed)` is not to be used lightly. Unless you have extreme requirements,
 this should not be used.

src/unchecked-uninit.md

@@ -137,7 +137,7 @@ also cannot use `&mut base_ptr.field` as that would be creating a
 reference. Thus, it is currently not possible to create a raw pointer to a field
 of a partially initialized struct, and also not possible to initialize a single
 field of a partially initialized struct. (a
-[solution to this problem](https://github.com/rust-lang/rfcs/pull/2582) is being
+[solution to this problem](https://github.com/rust-lang/rust/issues/64490) is being
 worked on).
 
 One last remark: when reading old Rust code, you might stumble upon the