Clear unwanted environment variable

This adds two things I forgot in
9a7d8df4 (Avoid accidentally using environment variables in sh scopes)

Mea culpa, the problem was that I was skipping matches with "filetype"
because that's usually just a hook parameter as in "WinSetOption filetype=.."

	rg --pcre2 '\b(?!filetype=)\w+=' rc/

So I missed these two cases where a shell variable is actually called "filetype".

The one in git.kak was not a problem because show_git_cmd_output is only
ever called with sane inputs.  However, file.kak does use the filetype
environment variable for many mime types, for example:

	filetype=somefiletype\''; echo -debug injection; nop '\' kak /dev/null

Will run the echo since /dev/null has mime type "inode/chardevice"

0 files changed, 0 insertions, 0 deletions