Doc: Provide a DocBook version of the beginqdoc and endqdoc macros

QDoc allows code-expanding macros to be defined so that the user can
abstract away common code in a simple to use command.

Furthermore, macros allows for a different expansion based on the
currently generated format so that format-specific requirements can be
satisfied when required.

Due to a certain bug in QDoc, when generating the DocBook format, QDoc
would expand an HTML specific macro definition when a DocBook specific
one was not provided.

As this bug is now being fixed, the DocBook format will lose some of the
output that it was previously generating.

For example, the "\beginqdoc" and "\endqdoc" macros are defined, for
HTML, to expand to the beginning of block-comment text, "/*!" and ending
of block-comment text, "*/".

To avoid losing the usage of "\beginqdoc" and "\endqdoc`" when
generating DocBook, an equivalent expansion of the macro is now provided
for the DocBook format.

Change-Id: I45fb54f1f56077771c091323a69fd63e09a910eb
Reviewed-by: Paul Wicking <[email protected]>
Reviewed-by: Topi Reiniö <[email protected]>

doc/global/macros.qdocconf

@@ -52,7 +52,9 @@ macro.mdash.DocBook       = "—"
 macro.pi.HTML             = "Π"
 macro.pi.DocBook          = "Π"
 macro.beginqdoc.HTML      = "/*!"
+macro.beginqdoc.DocBook   = "/*!"
 macro.endqdoc.HTML        = "*/"
+macro.endqdoc.DocBook        = "*/"
 macro.borderedimage       = "\\div {class=\"border\"} \\image \1\n\\enddiv"
 macro.examplecategory     = "\\meta category {\1}\n\\ingroup category \1"