:vana-inflector plural to singular rule list

Grammar fix courtesy of Scott, idiomatic fix pointed out by Xach.lisp

(defvar *plurals*
  '(("(quiz)$"                   "\\1zes")
    ("^(ox)$"                    "\\1en")
    ("([m|l])ouse$"              "\\1ice")
    ("(matr|vert|ind)(?:ix|ex)$" "\\1ices")
    ("(x|ch|ss|sh)$"             "\\1es")
    ("([^aeiouy]|qu)y$"          "\\1ies")
    ("(hive)$"                   "\\1s")
    ("(?:([^f])fe|([lr])f)$"     "\\1\\2ves")
    ("sis$"                      "ses")
    ("([ti])um$"                 "\\1a")
    ("(buffal|tomat)o$"          "\\1oes")
    ("(bu)s$"                    "\\1ses")
    ("(alias|status)$"           "\\1es")
    ("(octop)us$"                "\\1uses")
    ("(vir)us$"                  "\\1i")
    ("(ax|test)is$"              "\\1es")
    ("s$"                        "s")
    ("$"                         "s")))