UI: Display Sample Rate with proper formatting

UI/forms/OBSBasicSettings.ui

@@ -3685,19 +3685,19 @@
                    <item row="0" column="1">
                     <widget class="QComboBox" name="sampleRate">
                      <property name="currentText">
-                      <string notr="true">44.1khz</string>
+                      <string notr="true">44.1 kHz</string>
                      </property>
                      <property name="currentIndex">
                       <number>0</number>
                      </property>
                      <item>
                       <property name="text">
-                       <string>44.1khz</string>
+                       <string>44.1 kHz</string>
                       </property>
                      </item>
                      <item>
                       <property name="text">
-                       <string>48khz</string>
+                       <string>48 kHz</string>
                       </property>
                      </item>
                     </widget>

UI/window-basic-settings.cpp

@@ -2189,9 +2189,9 @@ void OBSBasicSettings::LoadAudioSettings()
 
 	const char *str;
 	if (sampleRate == 48000)
-		str = "48khz";
+		str = "48 kHz";
 	else
-		str = "44.1khz";
+		str = "44.1 kHz";
 
 	int sampleRateIdx = ui->sampleRate->findText(str);
 	if (sampleRateIdx != -1)
@@ -3253,7 +3253,7 @@ void OBSBasicSettings::SaveAudioSettings()
 	}
 
 	int sampleRate = 44100;
-	if (sampleRateStr == "48khz")
+	if (sampleRateStr == "48 kHz")
 		sampleRate = 48000;
 
 	if (WidgetChanged(ui->sampleRate))