doc: Add @nospell macro around proper names in documentation. * aspell-octave.en.pws: Remove proper names from Octave's custom dictionary. * doc/interpreter/audio.txi, doc/interpreter/diagperm.txi, doc/interpreter/diffeq.txi, doc/interpreter/emacs.txi, doc/interpreter/func.txi, doc/interpreter/geometry.txi, doc/interpreter/intro.txi, doc/interpreter/linalg.txi, doc/interpreter/numbers.txi, doc/interpreter/preface.txi, doc/interpreter/quad.txi, doc/interpreter/sparse.txi, libinterp/corefcn/colloc.cc, libinterp/corefcn/ellipj.cc, libinterp/corefcn/gammainc.cc, libinterp/corefcn/hess.cc, libinterp/corefcn/quadcc.cc, libinterp/corefcn/rand.cc, libinterp/corefcn/sqrtm.cc, libinterp/dldfcn/ccolamd.cc, libinterp/dldfcn/colamd.cc, libinterp/dldfcn/dmperm.cc, libinterp/dldfcn/symrcm.cc, scripts/general/quadgk.m, scripts/general/quadl.m, scripts/linear-algebra/commutation_matrix.m, scripts/linear-algebra/condest.m, scripts/linear-algebra/duplication_matrix.m, scripts/linear-algebra/expm.m, scripts/linear-algebra/housh.m, scripts/linear-algebra/krylov.m, scripts/linear-algebra/onenormest.m, scripts/linear-algebra/qzhess.m, scripts/optimization/fminsearch.m, scripts/optimization/glpk.m, scripts/signal/arch_fit.m, scripts/signal/bartlett.m, scripts/signal/blackman.m, scripts/signal/diffpara.m, scripts/signal/durbinlevinson.m, scripts/signal/hamming.m, scripts/signal/hanning.m, scripts/sparse/eigs.m, scripts/sparse/pcg.m, scripts/sparse/pcr.m, scripts/specfun/ellipke.m, scripts/special-matrix/gallery.m, scripts/special-matrix/invhilb.m, scripts/statistics/base/quantile.m, scripts/statistics/tests/kruskal_wallis_test.m, scripts/statistics/tests/manova.m, scripts/statistics/tests/mcnemar_test.m: Add @nospell macro around proper names in documentation.