Refactor: change "folder" to "directory" where needed.

This commit fixes every instance in which the word "folder" is
incorrectly used instead of "directory".

pages/linux/chattr.md

@@ -1,6 +1,6 @@
 # chattr
 
-> Change attributes of files or folders.
+> Change attributes of files or directories.
 
 - Make a file or directory immutable to changes and deletion, even by superuser:
 
@@ -10,6 +10,6 @@
 
 `chattr -i {{path/to/file_or_directory}}`
 
-- Recursively make an entire folder and contents immutable:
+- Recursively make an entire directory and contents immutable:
 
-`chattr -R +i {{folder}}`
+`chattr -R +i {{path/to/directory}}`