DOC: clarify crt-base usage

crt-base is also used after "crt" directive.

Signed-off-by: William Dauchy <w.dauchy@criteo.com>
diff --git a/doc/configuration.txt b/doc/configuration.txt
index d0bb974..9ac8985 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -800,8 +800,8 @@
 
 crt-base <dir>
   Assigns a default directory to fetch SSL certificates from when a relative
-  path is used with "crtfile" directives. Absolute locations specified after
-  "crtfile" prevail and ignore "crt-base".
+  path is used with "crtfile" or "crt" directives. Absolute locations specified
+  prevail and ignore "crt-base".
 
 daemon
   Makes the process fork into background. This is the recommended mode of