AUDIO: Update MIDI FluidSynth settings to match upstream

[ahrib]

ScummVM version 2.7.0
OS macos 13.4.1 (22F82)
Device Macbook Pro (Apple M1 Pro)

Requesting the MIDI FluidSynth default settings are updated to match the values in the upstream FluidSynth project.

Analysis

key	FS type	FS range	FS default	SVM type	SVM range	SVM default	comment
fluidsynth_chorus_activate (synth.chorus.active)	bool	(0,1)	1	bool	(0,1)	1	OK
fluidsynth_chorus_nr (synth.chorus.nr)	int	0 - 99	3 (~3% of max)	int	0 - 99	3 (~3% of max)	OK
fluidsynth_chorus_level (synth.chorus.level)	float	0.0 - 10.0	2.0 (20% of max)	int	0 - 100	100 (100% of max)	mismatch of value
fluidsynth_chorus_speed (synth.chorus.speed)	float	0.1 - 5.0	0.3 (6% of max)	int	10 - 500	30 (6% of max )	OK
fluidsynth_chorus_depth (synth.chorus.depth)	float	0.0 - 256.0	8.0 (~3% of max)	int	0 - 210	80 (~38% of max)	mismatch of range & value
fluidsynth_reverb_activate (synth.reverb.active)	bool	(0,1)	1	bool	(0,1)	1	OK
fluidsynth_reverb_roomsize (synth.reverb.room-size)	float	0.0 - 1.0	0.2 (20% of max)	int	0 - 100	20 (20% of max)	OK
fluidsynth_reverb_damping (synth.reverb.damp)	float	0.0 - 1.0	0.0 (0% of max)	int	0 - 100	0 (0% of max)	OK
fluidsynth_reverb_width (synth.reverb.width)	float	0.0 - 100.0	0.5 (0.5% of max)	int	0 - 100	1 (1% of max)	OK?
fluidsynth_reverb_level (synth.reverb.level)	float	0.0 - 1.0	0.9 (90% of max)	int	0 - 100	90 (90% of max)	OK

References
FS settings ​https://www.fluidsynth.org/api/fluidsettings.xml
ScummVM settings ​https://github.com/scummvm/scummvm/blob/master/doc/docportal/advanced_topics/configuration_file.rst

Proposed solution
Assuming values do not need to be scaled due to the difference in ranges used between ScummVM and Fluidsynth, suggesting the defaults are updated to the below.

Reverb

• Active True
• Room 20
• Damp 0
• Width 1
• Level 90

Chorus

• Active True
• N 3
• Level 20 (changed)
• Speed 30
• Depth 8 (changed)
• Type Sine

Thank you and keep up the awesome work.

[sev-]

Would be nice to get fixed before 2.8.0 release

[NMIError]

Settings have been updated to the ranges and default values used by the current FluidSynth version 2.3.4