fixed #186 (can't duplicate blocks with anchored comments)
smooth numerical values displayed in watchers
Type-check the SPLIT block's input before eval'ing it
Prevent watcher cells from growing wider as their contents becomes taller
Keep watchers onstage when hiding/showing them, fixes #195
"plain block prototype labels" preference setting

hide / show the (+) symbols in the block editor
Merge remote-tracking branch 'main/master'

* main/master:
  "plain block prototype labels" preference setting
  Keep watchers onstage when hiding/showing them, fixes #195
  Prevent watcher cells from growing wider as their contents becomes taller
  Type-check the SPLIT block's input before eval'ing it
  smooth numerical values displayed in watchers
  fixed #186 (can't duplicate blocks with anchored comments)