Normalize the final new line

Fixes #310
Some files had no newlines, some had 1 newline and some more than 1 newline.
Normalize them all to have only 1 newline at the end of all files.

pages/common/cat.md

@@ -8,4 +8,4 @@
 
 - Sequentially print the contents of *file1* and *file2* to the file *file3*.
 
-`cat {{file1}} {{file2}} > {{file3}}`
+`cat {{file1}} {{file2}} > {{file3}}`