Treat ";" as a valid range separator

Just as Vim does.
Allow empty range for command without name

As in :4 or :$, which makes ":;", ":,", ":, , " etc. valid commands.
Merge branch 'range-parsing-small-improvements'

Treat semicolon (";") as a valid range separator for command-line
commands.

Allow empty ranges for command without name (as in :4).