Improve doc

doc/sources/admin/exportedvars.rst

@@ -10,7 +10,7 @@ extracted from the users database by the
 :ref:`users module<start-authentication-users-and-password-databases>`.
 
 To create a variable, you've just to map a user attributes in LL::NG
-using ``Variables`` » ``Exported variables``. For each variable, The
+using ``Variables`` » ``Exported variables``. For each variable, the
 first field is the name which will be used in rules, macros or headers
 and the second field is the name of the user database field.
 

doc/sources/admin/rules_examples.rst

@@ -27,6 +27,16 @@ attribute you see there can be used in a rule!
     In Perl, ``eq`` means *Equal* and must be used on strings.
     ``==`` should be used only on numbers
 
+.. danger::
+
+    In Perl, ``@`` character means an array and ``%`` a hash!
+    If you want to write a macro with these characters, you have to escape them like this:
+
+::
+
+    $my_email = "$uid\@my-domain.com"
+    $percent = "$rate\%more"
+
 -  Restricting access to specific groups
 
 ::

doc/sources/admin/writingrulesand_headers.rst

@@ -173,14 +173,14 @@ use macros, local macros,...
 
 .. attention::
 
-
-
     -  Since many HTTP servers refuse non ascii headers, it is recommended
        to use encode_base64() function to transmit those headers
     -  Don't forget to add an empty string as second argument to
        encode_base64 function to avoid a "newline" characters insertion in
        result
-    -  Header names must contain only letters and "-" character
+    -  Header names must contain only letters and "-" character.
+       With Nginx, you can bypass this restriction by using
+       ``underscores_in_headers on;`` directive