Fix inconsistent grammar of "music mode", iina#5076 (iina#5080)

This commit will change the reference to music mode in the new setting
in the behavior section on the general tab to be in lowercase and
enclosed in double quotes to match the style of other references.

iina/Base.lproj/PrefGeneralViewController.xib

@@ -192,7 +192,7 @@
                 </button>
                 <button translatesAutoresizingMaskIntoConstraints="NO" id="fms-nd-RFo">
                     <rect key="frame" x="138" y="81" width="303" height="18"/>
-                    <buttonCell key="cell" type="check" title="Not while in Music Mode or only playing audio" bezelStyle="regularSquare" imagePosition="left" inset="2" id="yla-DT-YTx">
+                    <buttonCell key="cell" type="check" title="Not while in &quot;music mode&quot; or only playing audio" bezelStyle="regularSquare" imagePosition="left" inset="2" id="yla-DT-YTx">
                         <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
                         <font key="font" metaFont="system"/>
                     </buttonCell>

iina/en.lproj/PrefGeneralViewController.strings

@@ -152,8 +152,8 @@
 /* Class = "NSTextFieldCell"; title = "Pause/resume when:"; ObjectID = "xr2-rB-O0x"; */
 "xr2-rB-O0x.title" = "Pause/resume when:";
 
-/* Class = "NSButtonCell"; title = "Not while in Music Mode or only playing audio"; ObjectID = "yla-DT-YTx"; */
-"yla-DT-YTx.title" = "Not while in Music Mode or only playing audio";
+/* Class = "NSButtonCell"; title = "Not while in \"music mode\" or only playing audio"; ObjectID = "yla-DT-YTx"; */
+"yla-DT-YTx.title" = "Not while in \"music mode\" or only playing audio";
 
 /* Class = "NSMenuItem"; title = "Show welcome window"; ObjectID = "z9T-8h-1T0"; */
 "z9T-8h-1T0.title" = "Show welcome window";