Rollup merge of #40500 - estebank:turbofish-help, r=pnkfelix

Point out correct turbofish usage on `Foo<Bar<Baz>>`

Whenever we parse a chain of binary operations, as long as the first
operation is `<` and the subsequent operations are either `>` or `<`,
present the following diagnostic help:

    use `::<...>` instead of `<...>` if you meant to specify type arguments

This will lead to spurious recommendations on situations like
`2 < 3 < 4` but should be clear from context that the help doesn't apply
in that case.

Fixes #40396.

0 files changed, 0 insertions, 0 deletions