* Apply [[nodiscard]] to functions returning error codes
- applied [[nodiscard]] for all HRESULT, LRESULT, and NTSTATUS functions
- fixed IntelliSense declaration complaints leading to function not
implemented warnings
- deleted declared but never implemented functions
- fixed unused parameter warnings
How verified:
- bcz dbg
- opencon
- testcon
- VS2019 debug build
* - use LOG_IF_FAILED where applicable
- remove use of goto
- make MakeAltRasterFont return void
* - add missing [[nodiscard]]
- remove vestigal function declarations
- fix inconsistent function declaration
* Update manifest to correct 1903 version
While messing around with building with VS2019/14.2/etc, I noticed that the version we're using in the compatibility manifest doesn't match guidance for XAML Islands. This puts the version information from the public guidance into the manifest and leaves a link back to the page where I got this idea from.
* comment out unused params in IslandWindow::OnResize
