Update assets link

Author: abhro

docs/src/ecosystem.md

@@ -235,7 +235,7 @@ The joy of our community is the many astronomy and astrophysics packages availab
 
 [![curly braces](assets/code.png) Repository](https://github.com/JuliaAstro/AstroAngles.jl)
 
-[![book icon](../assets/book.png) Documentation](https://juliaastro.org/AstroAngles.jl/dev/)
+[![book icon](assets/book.png) Documentation](https://juliaastro.org/AstroAngles.jl/dev/)
 
 **String parsing and representation of angles**