Added example to PygmentsLexer docstring.

Author: jonathanslenders

prompt_toolkit/layout/lexers.py

@@ -150,6 +150,17 @@ class PygmentsLexer(Lexer):
  """
  Lexer that calls a pygments lexer.
 
+ Example::
+
+ from pygments.lexers import HtmlLexer
+ lexer = PygmentsLexer(HtmlLexer)
+
+ Note: Don't forget to also load a Pygments compatible style. E.g.::
+
+ from prompt_toolkit.styles.from_pygments import style_from_pygments
+ from pygments.styles import get_style_by_name
+ style = style_from_pygments(get_style_by_name('monokai'))
+
  :param pygments_lexer_cls: A `Lexer` from Pygments.
  :param sync_from_start: Start lexing at the start of the document. This
  will always give the best results, but it will be slow for bigger