Add an UnsupportedContentInCountryException and use it in YouTube Charts

This allows client to distinguish of a generic
ContentNotSupportedException, which hasn't fully its place for its usage
in YouTube Charts.

Author: AudricV

extractor/src/main/java/org/schabi/newpipe/extractor/exceptions/UnsupportedContentInCountryException.java

@@ -0,0 +1,20 @@
+package org.schabi.newpipe.extractor.exceptions;
+
+/**
+ * Exception for contents not supported in a country.
+ *
+ * <p>
+ * Unsupported content means content is not intentionally geographically restricted such as for
+ * distribution rights, for which {@link GeographicRestrictionException} should be used instead.
+ * </p>
+ */
+public class UnsupportedContentInCountryException extends ContentNotAvailableException {
+
+    public UnsupportedContentInCountryException(final String message) {
+        super(message);
+    }
+
+    public UnsupportedContentInCountryException(final String message, final Throwable cause) {
+        super(message, cause);
+    }
+}

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/kiosk/YoutubeTrendingMusicExtractor.java

@@ -2,9 +2,9 @@
 
 import org.schabi.newpipe.extractor.StreamingService;
 import org.schabi.newpipe.extractor.downloader.Downloader;
-import org.schabi.newpipe.extractor.exceptions.ContentNotSupportedException;
 import org.schabi.newpipe.extractor.exceptions.ExtractionException;
 import org.schabi.newpipe.extractor.exceptions.ParsingException;
+import org.schabi.newpipe.extractor.exceptions.UnsupportedContentInCountryException;
 import org.schabi.newpipe.extractor.linkhandler.ListLinkHandler;
 
 import javax.annotation.Nonnull;
@@ -23,7 +23,7 @@ public void onFetchPage(@Nonnull final Downloader downloader)
             throws IOException, ExtractionException {
         if (!YT_CHARTS_SUPPORTED_COUNTRY_CODES.contains(
                 getExtractorContentCountry().getCountryCode())) {
-            throw new ContentNotSupportedException(
+            throw new UnsupportedContentInCountryException(
                     "YouTube Charts doesn't support this country for trending music videos charts");
         }
         super.onFetchPage(downloader);