update some javadoc

app/src/main/java/org/fdroid/fdroid/compat/FileCompat.java

@@ -11,6 +11,12 @@ import org.fdroid.fdroid.data.SanitizedFile;
 import java.io.IOException;
 import java.lang.reflect.Method;
 
+/**
+ * This class works only with {@link SanitizedFile} instances to enforce
+ * filtering of the file names from files downloaded from the internet.
+ * This helps prevent things like SQL injection, shell command injection
+ * and other attacks based on putting various characters into filenames.
+ */
 public class FileCompat extends Compatibility {
 
     private static final String TAG = "FileCompat";

app/src/main/java/org/fdroid/fdroid/net/Downloader.java

@@ -117,11 +117,6 @@ public abstract class Downloader {
     }
 
     /**
-     * In a synchronous download (the usual usage of the Downloader interface),
-     * you will not be able to interrupt this because the thread will block
-     * after you have called download(). However if you use the AsyncDownloadWrapper,
-     * then it will use this mechanism to cancel the download.
-     *
      * After every network operation that could take a while, we will check if an
      * interrupt occured during that blocking operation. The goal is to ensure we
      * don't move onto another slow, network operation if we have cancelled the