feat: add useful links for Rust (#7397)

src/data/roadmaps/rust/content/108-web-development/105-poem.md

@@ -8,3 +8,4 @@ Learn more from the following resources:
 
 - [@official@Swagger API](https://github.com/swagger-api/swagger-ui)
 - [@official@Poem](https://docs.rs/poem/latest/poem/)
+- [@opensource@Poem](https://github.com/poem-web/poem)

src/data/roadmaps/rust/content/123-file-parsing/100-pdf-rs.md

@@ -5,3 +5,4 @@ pdf-rs is a crate that allows the developer to parse and manipulate data and met
 Learn more from the following resources:
 
 - [@official@PDF Documentation](https://docs.rs/pdf/latest/pdf/)
+- [@opensource@pdf-rs](https://github.com/pdf-rs/pdf)