make [`manual_map`] ignore types that contain `dyn`

[J-ZhengLi]

fixes: #12659

[manual_map] and [manual_filter] shares the same check logic, but this issue doesn't seems like it could affect manual_filter (?)

---

changelog: make [manual_map] ignore types that contain dyn

[rustbot]

r? @dswij

rustbot has assigned @dswij. They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[J-ZhengLi]

@rustbot ready

[xFrednet]

Hey, this is a ping from triage. @dswij can you give this PR a review? It's totally fine if you don't have the time right now, you can reassign the PR to a random team member using r? clippy.

@rustbot ready

[Alexendoo]

I'll take this one since I looked into it previously, r? me

[rustbot]

Failed to set assignee to me: invalid assignee

Note: Only org members with at least the repository "read" role, users with write permissions, or people who have commented on the PR may be assigned.

[J-ZhengLi]

~~I need more time on this~~

@rustbot author