Passing options to "less" with the LESS environment variable can
interfere with existing environment variables. There are at least two
problems, as the following examples show:
1. Alice is using git with colors. Now she decides to set LESS=i for
some reason. Suddenly, git displays codes in place of colors. Alice
likes codes, but she liked colors better!
2. Bob sets GIT_PAGER="less -RS", but does not set LESS. Git sets
LESS=FRSX before calling $GIT_PAGER. Now Bob wonders why his pager is
not always paging, when he explicitly tried to clear the F option.
Maybe Mallory has been messing with something?
By passing the options on the command line instead, both of these
situations are handled.