wt-status: Teach how to discard changes in the working directory

This is a question that comes up a lot in #git.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t7502-status.sh

@@ -46,6 +46,7 @@ cat > expect << \EOF
 #
 # Changed but not updated:
 #   (use "git add <file>..." to update what will be committed)
+#   (use "git checkout -- <file>..." to discard changes in working directory)
 #
 #	modified:   dir1/modified
 #
@@ -76,6 +77,7 @@ cat >expect <<EOF
 #
 # Changed but not updated:
 #   (use "git add <file>..." to update what will be committed)
+#   (use "git checkout -- <file>..." to discard changes in working directory)
 #
 #	modified:   dir1/modified
 #
@@ -104,6 +106,7 @@ cat >expect <<EOF
 #
 # Changed but not updated:
 #   (use "git add <file>..." to update what will be committed)
+#   (use "git checkout -- <file>..." to discard changes in working directory)
 #
 #	modified:   dir1/modified
 #
@@ -138,6 +141,7 @@ cat >expect <<EOF
 #
 # Changed but not updated:
 #   (use "git add <file>..." to update what will be committed)
+#   (use "git checkout -- <file>..." to discard changes in working directory)
 #
 #	modified:   dir1/modified
 #
@@ -174,6 +178,7 @@ cat > expect << \EOF
 #
 # Changed but not updated:
 #   (use "git add <file>..." to update what will be committed)
+#   (use "git checkout -- <file>..." to discard changes in working directory)
 #
 #	modified:   modified
 #
@@ -204,6 +209,7 @@ cat > expect << \EOF
 #
 # Changed but not updated:
 #   (use "git add <file>..." to update what will be committed)
+#   (use "git checkout -- <file>..." to discard changes in working directory)
 #
 #	modified:   dir1/modified
 #
@@ -267,6 +273,7 @@ cat >expect <<EOF
 #
 # Changed but not updated:
 #   (use "git add <file>..." to update what will be committed)
+#   (use "git checkout -- <file>..." to discard changes in working directory)
 #
 #	modified:   dir1/modified
 #
@@ -297,6 +304,7 @@ cat >expect <<EOF
 #
 # Changed but not updated:
 #   (use "git add <file>..." to update what will be committed)
+#   (use "git checkout -- <file>..." to discard changes in working directory)
 #
 #	modified:   dir1/modified
 #
@@ -326,6 +334,7 @@ cat >expect <<EOF
 # On branch master
 # Changed but not updated:
 #   (use "git add <file>..." to update what will be committed)
+#   (use "git checkout -- <file>..." to discard changes in working directory)
 #
 #	modified:   dir1/modified
 #
@@ -357,6 +366,7 @@ cat >expect <<EOF
 #
 # Changed but not updated:
 #   (use "git add <file>..." to update what will be committed)
+#   (use "git checkout -- <file>..." to discard changes in working directory)
 #
 #	modified:   dir1/modified
 #

wt-status.c

@@ -79,6 +79,7 @@ static void wt_status_print_dirty_header(struct wt_status *s,
 		color_fprintf_ln(s->fp, c, "#   (use \"git add <file>...\" to update what will be committed)");
 	else
 		color_fprintf_ln(s->fp, c, "#   (use \"git add/rm <file>...\" to update what will be committed)");
+	color_fprintf_ln(s->fp, c, "#   (use \"git checkout -- <file>...\" to discard changes in working directory)");
 	color_fprintf_ln(s->fp, c, "#");
 }