Better "Changed but not updated" message in git-status

Older Gits talked about "updating" a file to add its content to the
index, but this terminology is confusing for new users. "to stage" is far
more intuitive and already used in e.g. the "git stage" command name.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/gittutorial-2.txt b/Documentation/gittutorial-2.txt
index ecab0c0..7fe5848 100644
--- a/Documentation/gittutorial-2.txt
+++ b/Documentation/gittutorial-2.txt
@@ -373,7 +373,7 @@
 #
 #       new file: closing.txt
 #
-# Changed but not updated:
+# Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #
 #       modified: file.txt
diff --git a/t/t7508-status.sh b/t/t7508-status.sh
index c9300f3..4de3e27 100755
--- a/t/t7508-status.sh
+++ b/t/t7508-status.sh
@@ -44,7 +44,7 @@
 #
 #	new file:   dir2/added
 #
-# Changed but not updated:
+# Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #   (use "git checkout -- <file>..." to discard changes in working directory)
 #
@@ -73,7 +73,7 @@
 # Changes to be committed:
 #	new file:   dir2/added
 #
-# Changed but not updated:
+# Changes not staged for commit:
 #	modified:   dir1/modified
 #
 # Untracked files:
@@ -140,7 +140,7 @@
 #
 #	new file:   dir2/added
 #
-# Changed but not updated:
+# Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #   (use "git checkout -- <file>..." to discard changes in working directory)
 #
@@ -167,7 +167,7 @@
 # Changes to be committed:
 #	new file:   dir2/added
 #
-# Changed but not updated:
+# Changes not staged for commit:
 #	modified:   dir1/modified
 #
 # Untracked files not listed
@@ -202,7 +202,7 @@
 #
 #	new file:   dir2/added
 #
-# Changed but not updated:
+# Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #   (use "git checkout -- <file>..." to discard changes in working directory)
 #
@@ -260,7 +260,7 @@
 #
 #	new file:   dir2/added
 #
-# Changed but not updated:
+# Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #   (use "git checkout -- <file>..." to discard changes in working directory)
 #
@@ -320,7 +320,7 @@
 #
 #	new file:   ../dir2/added
 #
-# Changed but not updated:
+# Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #   (use "git checkout -- <file>..." to discard changes in working directory)
 #
@@ -392,7 +392,7 @@
 #
 #	<GREEN>new file:   dir2/added<RESET>
 #
-# Changed but not updated:
+# Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #   (use "git checkout -- <file>..." to discard changes in working directory)
 #
@@ -521,7 +521,7 @@
 #
 #	new file:   dir2/added
 #
-# Changed but not updated:
+# Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #   (use "git checkout -- <file>..." to discard changes in working directory)
 #
@@ -614,7 +614,7 @@
 #	new file:   dir2/added
 #	new file:   sm
 #
-# Changed but not updated:
+# Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #   (use "git checkout -- <file>..." to discard changes in working directory)
 #
@@ -673,7 +673,7 @@
 #	new file:   dir2/added
 #	new file:   sm
 #
-# Changed but not updated:
+# Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #   (use "git checkout -- <file>..." to discard changes in working directory)
 #
@@ -718,7 +718,7 @@
 
 cat >expect <<EOF
 # On branch master
-# Changed but not updated:
+# Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #   (use "git checkout -- <file>..." to discard changes in working directory)
 #
@@ -766,7 +766,7 @@
 #	new file:   dir2/added
 #	new file:   sm
 #
-# Changed but not updated:
+# Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #   (use "git checkout -- <file>..." to discard changes in working directory)
 #
@@ -819,7 +819,7 @@
 #
 #	modified:   sm
 #
-# Changed but not updated:
+# Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #   (use "git checkout -- <file>..." to discard changes in working directory)
 #
@@ -931,7 +931,7 @@
 #
 #	modified:   sm
 #
-# Changed but not updated:
+# Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #   (use "git checkout -- <file>..." to discard changes in working directory)
 #   (commit or discard the untracked or modified content in submodules)
@@ -989,7 +989,7 @@
 #
 #	modified:   sm
 #
-# Changed but not updated:
+# Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #   (use "git checkout -- <file>..." to discard changes in working directory)
 #
@@ -1067,7 +1067,7 @@
 
 cat > expect << EOF
 # On branch master
-# Changed but not updated:
+# Changes not staged for commit:
 #   (use "git add <file>..." to update what will be committed)
 #   (use "git checkout -- <file>..." to discard changes in working directory)
 #
diff --git a/wt-status.c b/wt-status.c
index fc2438f..d9f3d9f 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -88,7 +88,7 @@
 {
 	const char *c = color(WT_STATUS_HEADER, s);
 
-	color_fprintf_ln(s->fp, c, "# Changed but not updated:");
+	color_fprintf_ln(s->fp, c, "# Changes not staged for commit:");
 	if (!advice_status_hints)
 		return;
 	if (!has_deleted)