Switch the Renderable trait over to the returning a RenderError

src/renderer/errors.rs

@@ -14,6 +14,10 @@ pub enum RenderError<'a> {
         segment: String,
         elem: &'a dyn ContextElement,
     },
+    /// Attempting to render and unrenderable type (for example, an object without any filters)
+    CantRender {
+        elem: &'a dyn ContextElement,
+    },
 }
 
 #[derive(Clone)]
@@ -31,6 +35,7 @@ impl fmt::Display for RenderError<'_> {
             RenderError::WontWalk { segment, elem } => {
                 write!(f, "Failed to walk to {} from {:?}", segment, elem)
             }
+            RenderError::CantRender { elem } => write!(f, "Cant render {:?}", elem),
         }
     }
 }
@@ -45,6 +50,7 @@ impl fmt::Debug for RenderError<'_> {
             RenderError::WontWalk { segment, elem } => {
                 write!(f, "Failed to walk to {} from {:?}", segment, elem)
             }
+            RenderError::CantRender { elem } => write!(f, "Cant render {:?}", elem),
         }
     }
 }