doc: promote "git switch"

The new command "git switch" is added to avoid the confusion of
one-command-do-all "git checkout" for new users. They are also helpful
to avoid ambiguation context.

For these reasons, promote it everywhere possible. This includes
documentation, suggestions/advice from other commands...

The "Checking out files" progress line in unpack-trees.c is also updated
to "Updating files" to be neutral to both git-checkout and git-switch.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 12 insertions, 12 deletions

diff --git a/t/t2020-checkout-detach.sh b/t/t2020-checkout-detach.sh
index 743c724..b748db9 100755
--- a/t/t2020-checkout-detach.sh
+++ b/t/t2020-checkout-detach.sh
@@ -195,20 +195,20 @@ test_expect_success 'describe_detached_head prints no SHA-1 ellipsis when not as
 
 	# The first detach operation is more chatty than the following ones.
 	cat >1st_detach <<-EOF &&
-	Note: checking out 'HEAD^'.
+	Note: switching to 'HEAD^'.
 
 	You are in 'detached HEAD' state. You can look around, make experimental
 	changes and commit them, and you can discard any commits you make in this
-	state without impacting any branches by performing another checkout.
+	state without impacting any branches by switching back to a branch.
 
 	If you want to create a new branch to retain commits you create, you may
-	do so (now or later) by using -b with the checkout command again. Example:
+	do so (now or later) by using -c with the switch command. Example:
 
-	  git checkout -b <new-branch-name>
+	  git switch -c <new-branch-name>
 
-	Or undo this checkout with:
+	Or undo this operation with:
 
-	  git checkout -
+	  git switch -
 
 	Turn off this advice by setting config variable advice.detachedHead to false
 
@@ -277,20 +277,20 @@ test_expect_success 'describe_detached_head does print SHA-1 ellipsis when asked
 
 	# The first detach operation is more chatty than the following ones.
 	cat >1st_detach <<-EOF &&
-	Note: checking out 'HEAD^'.
+	Note: switching to 'HEAD^'.
 
 	You are in 'detached HEAD' state. You can look around, make experimental
 	changes and commit them, and you can discard any commits you make in this
-	state without impacting any branches by performing another checkout.
+	state without impacting any branches by switching back to a branch.
 
 	If you want to create a new branch to retain commits you create, you may
-	do so (now or later) by using -b with the checkout command again. Example:
+	do so (now or later) by using -c with the switch command. Example:
 
-	  git checkout -b <new-branch-name>
+	  git switch -c <new-branch-name>
 
-	Or undo this checkout with:
+	Or undo this operation with:
 
-	  git checkout -
+	  git switch -
 
 	Turn off this advice by setting config variable advice.detachedHead to false