`dd` deletes the current line`dd` deletes the current line
`dd` moves the cursor to the first non-space`dd` moves the cursor to the first non-space
`dd` moves the cursor up when deleting the last line`dd` moves the cursor up when deleting the last line
Remove duplicate index-of-first-non-blank
`dd` can delete the only line in a file`dd` can delete the only line in a file
Rename some locals for clarity