demos: redirect setup commands to /dev/null

Previously, we needed to remove this manually from screenshots.

demos/demo_juggle_conflicts.sh

@@ -3,16 +3,16 @@ set -euo pipefail
 . "$(dirname "$0")"/helpers.sh
 
 new_tmp_dir
-jj init --config-toml ui.allow-init-native=true
+jj init --config-toml ui.allow-init-native=true > /dev/null
 echo "first" > file
-jj branch create first
-jj commit -m 'first' 
+jj branch create first  > /dev/null
+jj commit -m 'first' > /dev/null
 echo "second" > file
-jj branch create second
-jj commit -m 'second' 
+jj branch create second > /dev/null
+jj commit -m 'second' > /dev/null
 echo "third" > file
-jj branch create third
-jj commit -m 'third' 
+jj branch create third > /dev/null
+jj commit -m 'third' > /dev/null
 
 comment "We are in a repo with three commits, all
 editing the same line:"

demos/demo_operation_log.sh

@@ -3,7 +3,7 @@ set -euo pipefail
 . "$(dirname "$0")"/helpers.sh
 
 new_tmp_dir
-jj git clone https://github.com/octocat/Hello-World
+jj git clone https://github.com/octocat/Hello-World > /dev/null
 cd Hello-World
 
 comment "We are in the octocat/Hello-World repo.
@@ -27,10 +27,10 @@ comment "The repo now looks like this:"
 run_command "jj log"
 comment "The most recent portion of the operation log
 is:"
-run_command "jj op log --color=always | head"
+run_command "jj op log | head"
 
 comment "Let's undo that rebase operation:"
-rebase_op=$(jj --color=never op log | grep '^◉  ' | sed '2q;d' | cut -b4-15)
+rebase_op=$(jj debug operation --display id --at-op @-- | head --bytes 8)
 run_command "jj undo $rebase_op"
 
 comment "Note that only the rebase was undone, and the

demos/demo_resolve_conflicts.sh

@@ -3,7 +3,7 @@ set -euo pipefail
 . "$(dirname "$0")"/helpers.sh
 
 new_tmp_dir
-jj git clone https://github.com/octocat/Hello-World
+jj git clone https://github.com/octocat/Hello-World > /dev/null
 cd Hello-World
 
 comment "We are on the master branch of the

demos/demo_working_copy.sh

@@ -3,7 +3,7 @@ set -euo pipefail
 . "$(dirname "$0")"/helpers.sh
 
 new_tmp_dir
-jj git clone https://github.com/octocat/Hello-World
+jj git clone https://github.com/octocat/Hello-World > /dev/null
 cd Hello-World
 
 comment "We are in the octocat/Hello-World repo.