Update 1-writing.md to improve readability (#6040)

docs/tutorial/1-writing.md

@@ -172,7 +172,7 @@ nothing else.
 For example, the image function expects a path to an image file.
 It would not make sense to pass, e.g., a paragraph of text or another image as
 the image's path parameter. That's why only strings are allowed here.
-On the contrary, strings work wherever content is expected because text is a
+In contrast, strings work wherever content is expected because text is a
 valid kind of content.
 </div>