This CL makes a number of small changes to dyn compatibility errors:
- "object safety" has been renamed to "dyn-compatibility" throughout
- "Convert to enum" suggestions are no longer generated when there
exists a type-generic impl of the trait or an impl for `dyn OtherTrait`
- Several error messages are reorganized for user readability
Additionally, the dyn compatibility error creation code has been
split out into functions.
cc #132713
cc #133267
Instead of
```
error[E0277]: the size for values of type `(dyn ThriftService<(), AssocType = _> + 'static)` cannot be known at compilation time
--> $DIR/issue-59324.rs:23:20
|
LL | fn with_factory<H>(factory: dyn ThriftService<()>) {}
| ^^^^^^^ doesn't have a size known at compile-time
```
output
```
error[E0277]: the size for values of type `(dyn ThriftService<(), AssocType = _> + 'static)` cannot be known at compilation time
--> $DIR/issue-59324.rs:23:29
|
LL | fn with_factory<H>(factory: dyn ThriftService<()>) {}
| ^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
```
