Add texinfo headers

--- a/docs/telega-ellit.org
+++ b/docs/telega-ellit.org
@@ -2,6 +2,10 @@
 #+TITLE: Telega Manual (v{{{eval(telega-version,t)}}})
 #+STARTUP: showall
 
+#+TEXINFO_DIR_CATEGORY: Emacs
+#+TEXINFO_DIR_TITLE: Telega: (telega-manual).
+#+TEXINFO_DIR_DESC: Telegram client for GNU Emacs
+
 #+MACRO: nl          (eval (concat "\n" (make-string (1- (string-to-number $1)) ?\s)))
 #+MACRO: user-option-ndv User Option: ~$1~ {{{nl(1)}}} {{{nl($2)}}} {{{vardoc($1, $2)}}} {{{nl(1)}}}
 #+MACRO: user-option User Option: ~$1~ {{{nl(1)}}} {{{nl($2)}}} {{{vardoc($1, $2)}}} {{{nl(1)}}} {{{nl($2)}}} Default value: {{{eval((ellit-org-pp-code-block $1 $2), t)}}}