Add new settings and settings dialog help tips

Add CombineNestedChapterTitles setting (#663)
Add SaveMetadataToFile setting
Add extended setting descriptions for select options

Source/LibationFileManager/Configuration.HelpText.cs

@@ -0,0 +1,36 @@
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+
+namespace LibationFileManager
+{
+    public partial class Configuration
+    {
+        public static ReadOnlyDictionary<string, string> HelpText { get; } = new Dictionary<string, string>
+        {
+            { nameof(CombineNestedChapterTitles),"""
+                If the book has nested chapters, e.g. a chapter named "Part 1"
+                that contains chapters "Chapter 1" and "Chapter 2", then combine
+                the chapter titles like the following example:
+
+                Part 1: Chapter 1
+                Part 1: Chapter 2
+                """},
+            {nameof(AllowLibationFixup), """
+                In addition to the options that are enabled if you allow
+                "fixing up" the audiobook, it does the following:
+                
+                * Sets the ©gen metadata tag for the genres.
+                * Adds the TCOM (@wrt in M4B files) metadata tag for the narrators.
+                * Unescapes the copyright symbol (replace &#169; with ©)
+                * Replaces the recording copyright (P) string with ℗
+                * Adds various other metadata tags recognized by AudiobookShelf
+                * Sets the embedded cover art image with cover art retrieved from Audible
+                """ },
+        }
+        .AsReadOnly();
+
+        public static string GetHelpText(string settingName)
+            => HelpText.TryGetValue(settingName, out var value) ? value : null;
+
+	}
+}

Source/LibationFileManager/Configuration.PersistentSettings.cs

@@ -73,9 +73,12 @@ namespace LibationFileManager
 
 		public bool Exists(string propertyName) => persistentDictionary.Exists(propertyName);
 
-		[Description("Set cover art as the folder's icon. (Windows and macOS only)")]
+		[Description("Set cover art as the folder's icon.")]
 		public bool UseCoverAsFolderIcon { get => GetNonString(defaultValue: false); set => SetNonString(value); }
 
+		[Description("Save audiobook metadata to metadata.json")]
+		public bool SaveMetadataToFile { get => GetNonString(defaultValue: false); set => SetNonString(value); }
+
 		[Description("Use the beta version of Libation\r\nNew and experimental features, but probably buggy.\r\n(requires restart to take effect)")]
 		public bool BetaOptIn { get => GetNonString(defaultValue: false); set => SetNonString(value); }
 
@@ -164,6 +167,9 @@ namespace LibationFileManager
 		[Description("Save cover image alongside audiobook?")]
 		public bool DownloadCoverArt { get => GetNonString(defaultValue: false); set => SetNonString(value); }
 
+		[Description("Combine nested chapter titles")]
+		public bool CombineNestedChapterTitles { get => GetNonString(defaultValue: false); set => SetNonString(value); }
+
 		[Description("Download clips and bookmarks?")]
 		public bool DownloadClipsBookmarks { get => GetNonString(defaultValue: false); set => SetNonString(value); }