Fix incorrect capital in comparison.md (#878)

Author: CodinCat

src/v2/guide/comparison.md

@@ -97,7 +97,7 @@ This is due to React's many heavy invariant checks in development mode, which he
 
 ### HTML & CSS
 
-In React, everything is Just JavaScript, which sounds very simple and elegant - until you dig deeper. The unfortunate reality is that reinventing HTML and CSS within JavaScript, while solving some issues of the traditional model, can also cause pain of its own. In Vue, we instead embrace web technologies and build on top of them. To show you what that means, we'll dive into some examples.
+In React, everything is just JavaScript, which sounds very simple and elegant - until you dig deeper. The unfortunate reality is that reinventing HTML and CSS within JavaScript, while solving some issues of the traditional model, can also cause pain of its own. In Vue, we instead embrace web technologies and build on top of them. To show you what that means, we'll dive into some examples.
 
 #### JSX vs Templates