doc: checkout: synchronize <pathspec> description

`git add` shows an example of good writing, follow it.

Signed-off-by: Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-checkout.txt

@@ -12,13 +12,13 @@ SYNOPSIS
 'git checkout' [-q] [-f] [-m] --detach [<branch>]
 'git checkout' [-q] [-f] [-m] [--detach] <commit>
 'git checkout' [-q] [-f] [-m] [[-b|-B|--orphan] <new_branch>] [<start_point>]
-'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [<tree-ish>] [--] <paths>...
-'git checkout' (-p|--patch) [<tree-ish>] [--] [<paths>...]
+'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [<tree-ish>] [--] <pathspec>...
+'git checkout' (-p|--patch) [<tree-ish>] [--] [<pathspec>...]
 
 DESCRIPTION
 -----------
 Updates files in the working tree to match the version in the index
-or the specified tree.  If no paths are given, 'git checkout' will
+or the specified tree.  If no pathspec was given, 'git checkout' will
 also update `HEAD` to set the specified branch as the current
 branch.
 
@@ -78,13 +78,13 @@ be used to detach `HEAD` at the tip of the branch (`git checkout
 +
 Omitting `<branch>` detaches `HEAD` at the tip of the current branch.
 
-'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [<tree-ish>] [--] <paths>...::
+'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [<tree-ish>] [--] <pathspec>...::
 
-	Overwrite paths in the working tree by replacing with the
-	contents in the index or in the `<tree-ish>` (most often a
-	commit).  When a `<tree-ish>` is given, the paths that
-	match the `<pathspec>` are updated both in the index and in
-	the working tree.
+	Overwrite the contents of the files that match the pathspec.
+	When the `<tree-ish>` (most often a commit) is not given,
+	overwrite working tree with the contents in the index.
+	When the `<tree-ish>` is given, overwrite both the index and
+	the working tree with the contents at the `<tree-ish>`.
 +
 The index may contain unmerged entries because of a previous failed merge.
 By default, if you try to check out such an entry from the index, the
@@ -336,7 +336,13 @@ leave out at most one of `A` and `B`, in which case it defaults to `HEAD`.
 	Tree to checkout from (when paths are given). If not specified,
 	the index will be used.
 
+\--::
+	Do not interpret any more arguments as options.
 
+<pathspec>...::
+	Limits the paths affected by the operation.
++
+For more details, see the 'pathspec' entry in linkgit:gitglossary[7].
 
 DETACHED HEAD
 -------------