CLSA-2026-1779271781 vim: Fix of 6 CVEs

CVE-2022-4292: also check winvalidanytab in didsetspelllang after SpellFileMissing autocmd - CVE-2023-4751: resetVIsualandresel at start of exbufferall to prevent UAF on Visual mark - CVE-2023-0054: bail out of dostringsub when vimregsub returns sublen = 0 - CVE-2022-2206: clamp cmdlinerow/msgrow...