UI: Fix case inconsistency in translation key

[skip crowdin-sync]

(cherry picked from commit e23b80151b37f1a7159ebc621c12ac9d38917aea)

UI/data/locale/en-US.ini

@@ -1147,7 +1147,7 @@ Basic.Settings.Audio.MeterDecayRate.Slow="Slow (Type II PPM)"
 Basic.Settings.Audio.PeakMeterType="Peak Meter Type"
 Basic.Settings.Audio.PeakMeterType.SamplePeak="Sample Peak"
 Basic.Settings.Audio.PeakMeterType.TruePeak="True Peak (Higher CPU usage)"
-Basic.Settings.Audio.MultiChannelWarning.Enabled="WARNING: Surround sound audio is enabled."
+Basic.Settings.Audio.MultichannelWarning.Enabled="WARNING: Surround sound audio is enabled."
 Basic.Settings.Audio.MultichannelWarning="If streaming, check to see if your streaming service supports both surround sound ingest and surround sound playback. Facebook 360 Live is one example where surround sound is fully supported. Although Facebook Live and YouTube Live both accept surround ingest, Facebook Live downmixes to stereo, and YouTube Live plays only two channels.\n\nOBS audio filters are compatible with surround sound, though VST plugin support isn't guaranteed."
 Basic.Settings.Audio.MultichannelWarning.Title="Enable surround sound audio?"
 Basic.Settings.Audio.MultichannelWarning.Confirm="Are you sure you want to enable surround sound audio?"