Another mode is:
If your editor HAS NO BLOCK comment option,
- Open a second instance of the editor (for example File=>New File...)
- From THE PREVIOUS file you are working on, select ONLY THE PART YOU WANT COMMENT
- Copy and paste it in the window of the new temporary file...
- Open the Edit menu, select REPLACE and input as string to be replaced '\n'
- input as replace string: '\n#'
- press the button 'replace ALL'
DONE
it WORKS with ANY editor