class_docstr: Lexer for the (g)roff typesetting language, supporting groff
  extensions. Mainly useful for highlighting manpage sources.
  
  .. versionadded:: 0.6
code: def analyse_text(text):
      if text[:1] != ".":
          return False
      if text[:3] == '.\\"':
          return True
      if text[:4] == ".TH ":
          return True
      if text[1:3].isalnum() and text[3].isspace():
          return 0.9
  
imports: import re
  from pygments.lexers.html import HtmlLexer, XmlLexer
  from pygments.lexers.javascript import JavascriptLexer
  from pygments.lexers.css import CssLexer
  from pygments.lexer import RegexLexer, DelegatingLexer, include, bygroups, using, this, do_insertions, default, words
  from pygments.token import Text, Comment, Operator, Keyword, Name, String, Number, Punctuation, Generic, Other
  from pygments.util import get_bool_opt, ClassNotFound
label_desc: Use image node_id 1 for calling the GroffLexer obj's underlying member method code with example usage: obj.analyse_text(text) and returns: False, True, True, int