Support Pitch, Rate and Volume commands properly in SAPI4 (#15271)
Summary of the issue:
Pitch, volume and rate changes can be embedded in speech sequences. However, the latter two were never implemented for SAPI4. Pitch support was implemented last year, but it was pretty strictly bound to the capital pitch change setting (i.e. it didn't respect the offset on the PitchCommand.
Description of user facing changes
Capital pitch change intervals might be bigger with some engines.
Description of development approach
Pitch, Volume and Rate commands are now implemented according to the respective control tags
Testing strategy:
Tested that capital pitch change still works, though the difference in pitch might be bigger now. However, I compared the capital pitch change with a real pitch change and the intervals are equal.
