Fix wording around Git working directory

episodes/14-collaboration-using-git.md

@@ -67,26 +67,26 @@ The diagram below shows a typical software development lifecycle with Git
 (in our case starting from making changes in a local branch that "tracks" a remote branch) and the commonly used commands to interact
 with different parts of the Git infrastructure, including:
 
-- **working directory** -
+- **working tree** -
   a local directory (including any subdirectories) where your project files live
   and where you are currently working.
-  It is also known as the "untracked" area of Git.
-  Any changes to files will be marked by Git in the working directory.
-  If you make changes to the working directory and do not explicitly tell Git to save them -
+  It is also known as the "untracked" area of Git or "working directory".
+  Any changes to files will be marked by Git in the working tree.
+  If you make changes to the working tree and do not explicitly tell Git to save them -
   you will likely lose those changes.
   Using `git add filename` command,
-  you tell Git to start tracking changes to file `filename` within your working directory.
+  you tell Git to start tracking changes to file `filename` within your working tree.
 - **staging area (index)** -
   once you tell Git to start tracking changes to files
   (with `git add filename` command),
   Git saves those changes in the staging area on your local machine.
   Each subsequent change to the same file needs to be followed by another `git add filename` command
   to tell Git to update it in the staging area.
-  To see what is in your working directory and staging area at any moment
+  To see what is in your working tree and staging area at any moment
   (i.e. what changes is Git tracking),
   run the command `git status`.
 - **local repository** -
-  stored within the `.git` directory of your project locally,
+  stored within the `.git` working tree of your project locally,
   this is where Git wraps together all your changes from the staging area
   and puts them using the `git commit` command.
   Each commit is a new, permanent snapshot (checkpoint, record) of your project in time,
@@ -106,14 +106,16 @@ with different parts of the Git infrastructure, including:
   is to always do a `git pull` before a `git push`, to ensure you have any latest changes before you push your own.
 
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+
 sequenceDiagram
-    Working Directory->>+Staging Area: git add
-    Staging Area->>+Local Repository Branch: git commit
-    Local Repository Branch->>+Remote Repository Branch: git push
-    Remote Repository Branch->>+Local Repository Branch: git fetch
-    Local Repository Branch->>+Working Directory:git merge
-    Remote Repository Branch->>+Working Directory: git pull (shortcut for git fetch followed by git merge for a 'tracking branch')
+    Working Tree->>+Staging Area: git add
+    Staging Area->>+Local Repository: git commit
+    Local Repository->>+Remote Repository: git push
+    Remote Repository->>+Local Repository: git fetch
+    Local Repository->>+Working Tree:git checkout
+    Local Repository->>+Working Tree:git merge
+    Remote Repository->>+Working Tree: git pull (shortcut for git fetch followed by git checkout/merge)
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