doc: Mark up some code examples

These blocks were misformatted in normal paragraph style in the
generated docs. Also, added \comment{} for comments within one code
example.

Signed-off-by: Benjamin Herr <ben@0x539.de>
doc: Mostly use apply-templates over value-of

xsl:value-of would strip all the nested markup of the selected doxygen
elements, so that \ref, \sa and \code formatting didn't actually work.

Signed-off-by: Benjamin Herr <ben@0x539.de>
doc: Translate doxygen <sp/> tags to spaces

Doxygen represents all spacing in code blocks with <sp/> tags, so these
need to be turned back into spaces.

Signed-off-by: Benjamin Herr <ben@0x539.de>
connection: Leave fd open in wl_connection_destroy

Calling close() on the same file descriptor that a previous call to
close() already closed is wrong, and racy if another thread received
that same file descriptor as a eg. new socket or actual file.

There are two situations where wl_connection_destroy() would close its
file descriptor and then another function up in the call chain would
close the same file descriptor:

  * When wl_client_create() fails after calling wl_connection_create(),
    it will call wl_connection_destroy() before returning. However, its
    caller will always close the file descriptor if wl_client_create()
    fails.

  * wl_display_disconnect() unconditionally closes the display file
    descriptor and also calls wl_connection_destroy().

So these two seem to expect wl_connection_destroy() to leave the file
descriptor open. The other caller of wl_connection_destroy(),
wl_client_destroy(), does however expect wl_connection_destroy() to
close its file descriptor, alas.

This patch changes wl_connection_destroy() to indulge this majority of
two callers by simply not closing the file descriptor. For the benefit
of wl_client_destroy(), wl_connection_destroy() then returns the
unclosed file descriptor so that wl_client_destroy() can close it
itself.

Since wl_connection_destroy() is a private function called from few
places, changing its semantics seemed like the more expedient way to
address the double-close() problem than shuffling around the logic in
wl_client_create() to somehow enable it to always avoid calling
wl_connection_destroy().

Signed-off-by: Benjamin Herr <ben@0x539.de>
Reviewed-by: Marek Chalupa <mchqwerty@gmail.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
cosmetic: convert some function returns from int to bool

[Pekka Paalanen: change is_nullable_type() return value to bool.]

Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Protocol : Added destructor to wl_data_device interface

[Pekka Paalanen: removed trailing whitespace, adjust bz link.]

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=81745
Signed-off-by: kabeer khan <kabeer.khan@samsung.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>