Update line_features.md

More editing for clarity. I think this is what you really meant to say ????

Please feel free to edit.

doc/sphinx/user_manual/concepts/line_features.md

@@ -2,4 +2,4 @@
 Line features
 =============================
 
-Line features are named after that they look like  line on a map, but these lines still represent 3D objects, like we saw in {ref}`part:user_manual:chap:concepts:sec:painting_the_world`, where we used the `subducting plate` feature.  An other example of a line feature is the `fault` feature. We will explain how these features work in practice in the {ref}`part:user_manual:chap:basic_starter_tutorial:sec:index`. 
+Line features look like lines on a map but are used to represent 3D objects. For example, in {ref}`part:user_manual:chap:concepts:sec:painting_the_world`, this feature is used in the `subducting plate` feature.  Another example of a line feature is the `fault` feature. We will explain how these features work in practice in {ref}`part:user_manual:chap:basic_starter_tutorial:sec:index`.