Documentation: Clarify location of git-settings.xml

Author: kwin

maven-scm-providers/maven-scm-providers-git/maven-scm-provider-git-commons/src/main/mdo/git-settings.mdo

@@ -25,7 +25,7 @@
   xml.schemaLocation="http://maven.apache.org/xsd/scm-git-${version}.xsd">
   <id>git-settings</id>
   <name>Git</name>
-  <description>Git Provider Model</description>
+  <description>Git Settings, read from ${user.home}/.scm/git-settings.xml</description>
   <defaults>
     <default>
       <key>package</key>