These assists always generate a snippet regardless of if the LSP client does or doesn't support the snippet text edit capability:

• extract_expressions_from_format_string fix: Only generate snippets for extract_expressions_from_format_string if snippets are supported #17333
• generate_constant
• generate_mut_trait_impl fix: In generate_mut_trait_impl, don't add a tabstop if the client does not support snippets #20336

They unfortunately weren't captured in the initial batch of migrations to the new structured snippet API as they didn't use {insert,replace}_snippet, which is what I used to figure out which assists needed migrating.

Note that because the structured snippet API (add_{tabstop,placeholder}_*) relies on syntax nodes, they must also be migrated away from using insert and replace.