Fix seealso HTML links when using Texinfo 4.X (bug #38862). Use the prefix 'docX' instead of 'doc-' for Texinfo references. * doc/interpreter/arith.txi, doc/interpreter/basics.txi, doc/interpreter/container.txi, doc/interpreter/func.txi, doc/interpreter/java.txi, doc/interpreter/matrix.txi, doc/interpreter/munge-texi.pl, doc/interpreter/package.txi, doc/interpreter/plot.txi, doc/interpreter/stats.txi, doc/interpreter/strings.txi, doc/interpreter/system.txi, doc/interpreter/var.txi, doc/interpreter/vectorize.txi, libinterp/corefcn/qz.cc, libinterp/corefcn/regexp.cc, libinterp/interpfcn/error.cc, scripts/general/accumarray.m, scripts/general/structfun.m, scripts/miscellaneous/setfield.m, scripts/optimization/fminbnd.m, scripts/optimization/fzero.m, scripts/optimization/lsqnonneg.m: Use the prefix 'docX' instead of 'doc-' for Texinfo references.