Enable clippy::too_many_arguments (#8734)

This PR enables the
[`clippy::too_many_arguments`](https://rust-lang.github.io/rust-clippy/master/index.html#/too_many_arguments)
rule.

I opted to add `#[allow(clippy::too_many_arguments)]` on the individual
violations, as reworking them to take fewer arguments is a more involved
task.

Release Notes:

- N/A

crates/rich_text/src/rich_text.rs

@@ -124,6 +124,7 @@ impl RichText {
     }
 }
 
+#[allow(clippy::too_many_arguments)]
 pub fn render_markdown_mut(
     block: &str,
     mut mentions: &[Mention],