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

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

pages/common/git-worktree.md

@@ -3,18 +3,18 @@
 > Manage multiple working trees attached to the same repository.
 > Homepage: <https://git-scm.com/docs/git-worktree>.
 
-- Create a new folder with the specified branch checked out into it:
+- Create a new directory with the specified branch checked out into it:
 
-`git worktree add {{path/to/folder}} {{branch}}`
+`git worktree add {{path/to/directory}} {{branch}}`
 
-- Create a new folder with a new branch checked out into it:
+- Create a new directory with a new branch checked out into it:
 
-`git worktree add {{path/to/folder}} -b {{new_branch}}`
+`git worktree add {{path/to/directory}} -b {{new_branch}}`
 
 - List all the working directories attached to this repository:
 
 `git worktree list`
 
-- Remove a worktree (after deleting worktree folder):
+- Remove a worktree (after deleting worktree directory):
 
 `git worktree prune`