Move the impl of Source to the same file as the definition of the struct.

src/parser/lesser_element.rs

@@ -1,5 +1,6 @@
 use super::object::Object;
 use super::object::TextMarkup;
+use super::source::Source;
 
 #[derive(Debug)]
 pub struct Paragraph<'s> {
@@ -28,3 +29,21 @@ impl<'s> Paragraph<'s> {
         }
     }
 }
+
+impl<'s> Source<'s> for Paragraph<'s> {
+    fn get_source(&'s self) -> &'s str {
+        self.source
+    }
+}
+
+impl<'s> Source<'s> for TableCell<'s> {
+    fn get_source(&'s self) -> &'s str {
+        self.source
+    }
+}
+
+impl<'s> Source<'s> for Comment<'s> {
+    fn get_source(&'s self) -> &'s str {
+        self.source
+    }
+}