Merge pull request #2134 from jmdavis/dstyle2

Adjust section for ddoc comments in style guide.

Author: wilzbach

dstyle.dd

@@ -421,9 +421,9 @@ bool isPositive(int number)
 }
 ---
     $(LI Text in sections (e.g. `Params:`, `Returns:`, `See_Also`) should be indented by one level if it spans more than the line of the section.)
-    $(LI Documentation comments should not use more than two stars `/**` in the header line.)
-    $(LI Block comments (`/**`) should be used - not nesting block comments (`/++`))
-    $(LI Global functions shouldn't indent their documentation block nor use stars as indentation.)
+    $(LI Documentation comments should not use more than two stars `/**` or two pluses `/++` in the header line.)
+    $(LI Either Block comments (`/**`) or nesting block comments (`/++`) should be used except when the ddoc comment is a ditto comment such as `/// Ditto`)
+    $(LI Documentation comments should not have leading stars or zeroes on each line.)
     $(LI Text example blocks should use three dashes (`---`) only.)
 )