Add svg file check method

Author: Lamparter

src/Files.Shared/Helpers/FileExtensionHelpers.cs

@@ -386,6 +386,16 @@ public static bool IsTextFile(string? fileExtensionToCheck)
 			return HasExtension(fileExtensionToCheck, ".txt");
 		}
 
+		/// <summary>
+		/// Checks if the file extension represents an SVG file.
+		/// </summary>
+		/// <param name="fileExtensionToCheck">The file extension to check</param>
+		/// <returns><c>true</c> if the <c>filePathToCheck</c> is an SVG file; otherwise, <c>false</c>.</returns>
+		public static bool IsSvgFile(string? fileExtensionToCheck)
+		{
+			return HasExtension(fileExtensionToCheck, ".svg");
+		}
+
 		/// <summary>
 		/// Check if the file is signable.
 		/// </summary>