docs: add empty lines

Author: kenjis

user_guide_src/source/intro/index.rst

@@ -7,13 +7,16 @@ people who build web sites using PHP. Its goal is to enable you to
 develop projects much faster than you could if you were writing code
 from scratch, by providing a rich set of libraries for commonly needed
 tasks, as well as a simple interface and logical structure to access
-these libraries. CodeIgniter lets you creatively focus on your project
+these libraries.
+
+CodeIgniter lets you creatively focus on your project
 by minimizing the amount of code needed for a given task.
 
 Where possible, CodeIgniter has been kept as flexible as possible,
 allowing you to work in the way you want, not being forced into working
 any certain way. The framework can have core parts easily extended
 or completely replaced to make the system work the way you need it to.
+
 In short, CodeIgniter is the malleable framework that tries to provide
 the tools you need while staying out of the way.