Remove whitespace from line endings

Author: vanjacosic

src/doc/book/getting-started.md

@@ -230,12 +230,12 @@ $ cd hello_world
 
 ## Writing and Running a Rust Program
 
-We need to create a source file for our Rust program. Rust files always end 
-in a *.rs* extension. If you are using more than one word in your filename, 
-use an underscore to separate them; for example, you would use 
+We need to create a source file for our Rust program. Rust files always end
+in a *.rs* extension. If you are using more than one word in your filename,
+use an underscore to separate them; for example, you would use
 *my_program.rs* rather than *myprogram.rs*.
 
-Now, make a new file and call it *main.rs*. Open the file and type 
+Now, make a new file and call it *main.rs*. Open the file and type
 the following code:
 
 ```rust