Use StringBuilder.Append(char) instead of (string)

CA1834: Use StringBuilder.Append(char) for single character strings
https://docs.microsoft.com/en-us/dotnet/fundamentals/code-analysis/quality-rules/ca1834

Author: decriptor

src/TaglibSharp/Id3v2/Frames/AttachmentFrame.cs

@@ -506,7 +506,7 @@ public override string ToString ()
 
 			if (string.IsNullOrEmpty (Description)) {
 				builder.Append (Description);
-				builder.Append (" ");
+				builder.Append (' ');
 			}
 
 			builder.AppendFormat (System.Globalization.CultureInfo.InvariantCulture, "[{0}] {1} bytes", MimeType, Data.Count);

src/TaglibSharp/Id3v2/Frames/TextIdentificationFrame.cs

@@ -960,7 +960,7 @@ protected override ByteVector RenderFields (byte version)
 				StringBuilder data = new StringBuilder ();
 				foreach (string s in text) {
 					if (!prev_value_indexed) {
-						data.Append (";").Append (s);
+						data.Append (';').Append (s);
 						continue;
 					}
 
@@ -1192,7 +1192,7 @@ public override string[] Text {
 		/// </returns>
 		public override string ToString ()
 		{
-			return new StringBuilder ().Append ("[")
+			return new StringBuilder ().Append ('[')
 				.Append (Description)
 				.Append ("] ")
 				.Append (base.ToString ()).ToString ();

src/TaglibSharp/Id3v2/Frames/UrlLinkFrame.cs

@@ -677,7 +677,7 @@ public override string[] Text {
 		/// </returns>
 		public override string ToString ()
 		{
-			return new StringBuilder ().Append ("[")
+			return new StringBuilder ().Append ('[')
 			  .Append (Description)
 			  .Append ("] ")
 			  .Append (base.ToString ()).ToString ();

src/TaglibSharp/Id3v2/Tag.cs

@@ -979,14 +979,14 @@ protected void Parse (ByteVector data, File file, long position, ReadStyle style
 			if (tdat != null) {
 				string tdat_text = tdat.ToString ();
 				if (tdat_text.Length == 4) {
-					tdrc_text.Append ("-").Append (tdat_text, 0, 2).Append ("-").Append (tdat_text, 2, 2);
+					tdrc_text.Append ('-').Append (tdat_text, 0, 2).Append ('-').Append (tdat_text, 2, 2);
 
 					// Add the time
 					if (time != null) {
 						string time_text = time.ToString ();
 
 						if (time_text.Length == 4)
-							tdrc_text.Append ("T").Append (time_text, 0, 2).Append (":").Append (time_text, 2, 2);
+							tdrc_text.Append ('T').Append (time_text, 0, 2).Append (':').Append (time_text, 2, 2);
 
 						RemoveFrames (FrameType.TIME);
 					}

src/TaglibSharp/Mpeg/AudioHeader.cs

@@ -488,10 +488,10 @@ public string Description {
 				builder.Append ("MPEG Version ");
 				switch (Version) {
 				case Version.Version1:
-					builder.Append ("1");
+					builder.Append ('1');
 					break;
 				case Version.Version2:
-					builder.Append ("2");
+					builder.Append ('2');
 					break;
 				case Version.Version25:
 					builder.Append ("2.5");