worktree: use 'worktree' over 'working tree'

It is helpful to distinguish between a 'working tree' and a 'worktree'.
A worktree contains a working tree plus additional metadata. This
metadata includes per-worktree refs and worktree-specific config.

This is the first of multiple changes to git-worktree.txt, restricted to
the DESCRIPTION section.

Helped-by: Junio C Hamano <[email protected]>
Signed-off-by: Derrick Stolee <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: derrickstolee

Documentation/git-worktree.txt

@@ -25,45 +25,49 @@ Manage multiple working trees attached to the same repository.
 
 A git repository can support multiple working trees, allowing you to check
 out more than one branch at a time.  With `git worktree add` a new working
-tree is associated with the repository.  This new working tree is called a
-"linked working tree" as opposed to the "main working tree" prepared by
-linkgit:git-init[1] or linkgit:git-clone[1].
-A repository has one main working tree (if it's not a
-bare repository) and zero or more linked working trees. When you are done
-with a linked working tree, remove it with `git worktree remove`.
+tree is associated with the repository, along with additional metadata
+that differentiates that working tree from others in the same repository.
+The working tree, along with this metadata, is called a "worktree".
+
+This new worktree is called a "linked worktree" as opposed to the "main
+worktree" prepared by linkgit:git-init[1] or linkgit:git-clone[1].
+A repository has one main worktree (if it's not a bare repository) and
+zero or more linked worktrees. When you are done with a linked worktree,
+remove it with `git worktree remove`.
 
 In its simplest form, `git worktree add <path>` automatically creates a
 new branch whose name is the final component of `<path>`, which is
 convenient if you plan to work on a new topic. For instance, `git
 worktree add ../hotfix` creates new branch `hotfix` and checks it out at
-path `../hotfix`. To instead work on an existing branch in a new working
-tree, use `git worktree add <path> <branch>`. On the other hand, if you
-just plan to make some experimental changes or do testing without
-disturbing existing development, it is often convenient to create a
-'throwaway' working tree not associated with any branch. For instance,
-`git worktree add -d <path>` creates a new working tree with a detached
-`HEAD` at the same commit as the current branch.
+path `../hotfix`. To instead work on an existing branch in a new worktree,
+use `git worktree add <path> <branch>`. On the other hand, if you just
+plan to make some experimental changes or do testing without disturbing
+existing development, it is often convenient to create a 'throwaway'
+worktree not associated with any branch. For instance,
+`git worktree add -d <path>` creates a new worktree with a detached `HEAD`
+at the same commit as the current branch.
 
 If a working tree is deleted without using `git worktree remove`, then
 its associated administrative files, which reside in the repository
 (see "DETAILS" below), will eventually be removed automatically (see
 `gc.worktreePruneExpire` in linkgit:git-config[1]), or you can run
-`git worktree prune` in the main or any linked working tree to
-clean up any stale administrative files.
+`git worktree prune` in the main or any linked worktree to clean up any
+stale administrative files.
 
-If a linked working tree is stored on a portable device or network share
-which is not always mounted, you can prevent its administrative files from
-being pruned by issuing the `git worktree lock` command, optionally
-specifying `--reason` to explain why the working tree is locked.
+If the working tree for a linked worktree is stored on a portable device
+or network share which is not always mounted, you can prevent its
+administrative files from being pruned by issuing the `git worktree lock`
+command, optionally specifying `--reason` to explain why the worktree is
+locked.
 
 COMMANDS
 --------
 add <path> [<commit-ish>]::
 
-Create `<path>` and checkout `<commit-ish>` into it. The new working directory
-is linked to the current repository, sharing everything except working
-directory specific files such as `HEAD`, `index`, etc. As a convenience,
-`<commit-ish>` may be a bare "`-`", which is synonymous with `@{-1}`.
+Create a worktree at `<path>` and checkout `<commit-ish>` into it. The new worktree
+is linked to the current repository, sharing everything except per-worktree
+files such as `HEAD`, `index`, etc. As a convenience, `<commit-ish>` may
+be a bare "`-`", which is synonymous with `@{-1}`.
 +
 If `<commit-ish>` is a branch name (call it `<branch>`) and is not found,
 and neither `-b` nor `-B` nor `--detach` are used, but there does