doc: make previous line of certificate example end with "::"
Before this patch, certificate example is formatted just as normal
text.
--- a/mercurial/help/config.txt Mon Aug 01 06:08:27 2016 +0900
+++ b/mercurial/help/config.txt Mon Aug 01 06:08:27 2016 +0900
@@ -1082,7 +1082,7 @@
This option has no effect if the per-host ``fingerprints`` option
is set.
- The format of the file is as follows:
+ The format of the file is as follows::
-----BEGIN CERTIFICATE-----
... (certificate in base64 PEM encoding) ...