Changed line matching vim swapfiles to use all names it will create

As described in the [vim reference manual page on recovery](http://vimdoc.sourceforge.net/htmldoc/recover.html#E326), it will create swap files <code>.swp</code> through <code>.saa</code>. The [vim user manual page on recovery](http://vimdoc.sourceforge.net/htmldoc/usr_11.html#11.2) suggests to use <code>.s[uvw][a-z]</code>, but it will still create files outside this range, e.g. <code>.sta</code> if enough instances are opened.