Use actual name of imported crate in generated code

[Kijewski]

Using proc-macro-crate (or extracting its logic) it would be possible to emit e.g. ::askama_axum::… instead of ::askama::… if the user only used the integration crate instead of the parent one. Also, if the user renames the import like [dependencies] my_askama = { package = "askama" }, we could still generate working code.

The major drawback is that proc-macro-crate uses toml_edit which has a ton of dependencies. And actually in https://github.com/djc/askama/pull/780 we deliberately went away from using toml_edit for this exact reason. proc-macro-crate is only ~200 lines and liberally licensed as MIT OR Apache-2.0 like askama, so I guess we could simply extract or reproduce its logic using basic-toml. Is this case we would have to depend on serde, but chances are that any user of askama uses serde as well in their project.

We already depend on basic-toml & serde if the feature "config" is enabled.

[djc]

Hmm, I'm not convinced that's worth the added complexity.

[Kijewski]

Yeah, you're right. Users probably would even expect renamed dependencies to work.