Update files documentation

Sources/SwiftKit/Files/BundleFileFinder.swift

@@ -11,12 +11,18 @@ public class BundleFileFinder: FileFinder {
     
     private let bundle: Bundle
     
+    /**
+     Find files with names that start with a certain prefix.
+     */
     public func findFilesWithFileNamePrefix(_ prefix: String) -> [String] {
         let format = "self BEGINSWITH %@"
         let predicate = NSPredicate(format: format, argumentArray: [prefix])
         return findFilesWithPredicate(predicate)
     }
     
+    /**
+     Find files with names that end with a certain suffix.
+     */
     public func findFilesWithFileNameSuffix(_ suffix: String) -> [String] {
         let format = "self ENDSWITH %@"
         let predicate = NSPredicate(format: format, argumentArray: [suffix])

Sources/SwiftKit/Files/FileFinder.swift

@@ -6,6 +6,13 @@ import Foundation
  */
 public protocol FileFinder {
     
+    /**
+     Find files with names that start with a certain prefix.
+     */
     func findFilesWithFileNamePrefix(_ prefix: String) -> [String]
+    
+    /**
+     Find files with names that end with a certain suffix.
+     */
     func findFilesWithFileNameSuffix(_ suffix: String) -> [String]
 }

Sources/SwiftKit/Files/StandardFileExporter.swift

@@ -28,11 +28,25 @@ public class StandardFileExporter: FileExporter {
         case invalidUrl
     }
     
+    /**
+     Delete a previously exported file.
+     
+     This function should be called when you are done with a
+     file, to avoid that the file system fills up with files
+     that are no longer used.
+     */
     public func deleteFile(named fileName: String) {
         guard let url = getFileUrl(forFileName: fileName) else { return }
         try? fileManager.removeItem(at: url)
     }
     
+    /**
+     Export the provided data to a certain file.
+     
+     The resulting file url will depend on the file exporter
+     implementation. For instance, the `StandardFileExporter`
+     will store the file in the specified directory.
+     */
     public func export(data: Data, to fileName: String, completion: @escaping Completion) {
         guard let url = getFileUrl(forFileName: fileName) else { return completion(.failure(ExportError.invalidUrl)) }
         tryWrite(data: data, to: url, completion: completion)