Harmonize notation of admonition blocks in documentation

There were several different notations used for NOTE and IMPORTANT
sections that sometimes didn't even render correctly.

Change-Id: I744cb0922f4bb4c99282984a487761f2c1bd6d4a
Signed-off-by: Michael Ochmann <michael.ochmann@sap.com>

Documentation/config-gitweb.txt

diff --git a/Documentation/config-gitweb.txt b/Documentation/config-gitweb.txt
index 3755cff..fcfd0e1 100644
--- a/Documentation/config-gitweb.txt
+++ b/Documentation/config-gitweb.txt
@@ -145,7 +145,8 @@
 AllowOverride None
 ----
 
-*NOTE* This may have already been added by yum/apt-get. If that's the case, leave as
+[NOTE]
+This may have already been added by yum/apt-get. If that's the case, leave as
 is.
 
 ===== Restart the Apache Web Server