sw content controls: select the content on click when showing placeholder

- teach SwCursorShell::GetContentAtPos() about a new IsAttrAtPos::ContentControl

- add a new SwCursorShell::GotoFormatContentControl() to select a
content control, and a SwWrtShell::GotoContentControl() wrapper around
it

- combine these together in SwEditWin::MouseButtonUp()

The intention is that when you open a document and you click on a
placeholder text like "Click here to enter text", then this content is
pre-selected (so typing overwrites it), but typing real content there
disables this behavior.

Change-Id: Ia539865da7b18c41cbfb398282842bdb2e25f0bc
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/132652
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins

0 files changed, 0 insertions, 0 deletions