Refactor: improve consistency of the term "directory".

This commit changes the term "folder" to "directory" in every
instance where the first is used in an example description, but the
second is used in the example code, and vice versa.

pages/common/cpio.md

@@ -7,7 +7,7 @@
 
 `echo "{{file1}} {{file2}} {{file3}}" | cpio -o > {{archive.cpio}}`
 
-- Copy all files and folders in a directory and add them [o]nto an archive, in [v]erbose mode:
+- Copy all files and directories in a directory and add them [o]nto an archive, in [v]erbose mode:
 
 `find {{path/to/directory}} | cpio -ov > {{archive.cpio}}`