Add link to glob definition for include directive

diff --git a/doc/arm/reference.rst b/doc/arm/reference.rst
index 50b38e0fed35e6f96a08b8ee88b115bed18d8c37..f5093ec61b53e3665585b236b7a1d47581593839 100644 (file)
--- a/doc/arm/reference.rst
+++ b/doc/arm/reference.rst
@@ -173,13 +173,15 @@ the following examples:
 ``include`` Directive Definition and Usage
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-The include directive inserts the specified file (or files if a valid glob
-expression is detected) at the point where the include directive is
+The include directive inserts the specified file (or files if a valid `glob
+expression`_ is detected) at the point where the include directive is
 encountered. The include directive facilitates the administration of
 configuration files by permitting the reading or writing of some things but not
 others. For example, the statement could include private keys that are readable
 only by the name server.
 
+.. _`glob expression`: https://man7.org/linux/man-pages/man7/glob.7.html
+
 .. _address_match_lists:
 .. _address_match_list: