When parsing manual in languages with non-ascii letters, the section 
names using non-ascii letters are not added to the table of content.

  I noticed the bug reading the French bash manual: the quite useful 
"COMMANDES INTERNES DE l'INTERPRÉTEUR" section does not appear (SHELL 
BUILTIN COMMAND). (because of the É letter)

  I propose to use Character class instead of ascii interval in the 
appropriate regexp defvar. It should not change anything for english 
manual and it should work for many other languages.

  It works great for the bash manual in French.
  Grégory Mounié