Fix checkstyle

Author: subhramit

jablib/src/main/java/org/jabref/logic/importer/fetcher/AstrophysicsDataSystem.java

@@ -17,7 +17,6 @@
 import org.jabref.logic.formatter.bibtexfields.NormalizeNamesFormatter;
 import org.jabref.logic.formatter.bibtexfields.RemoveEnclosingBracesFormatter;
 import org.jabref.logic.formatter.bibtexfields.RemoveNewlinesFormatter;
-import org.jabref.logic.help.HelpFile;
 import org.jabref.logic.importer.EntryBasedParserFetcher;
 import org.jabref.logic.importer.FetcherException;
 import org.jabref.logic.importer.IdBasedParserFetcher;

jablib/src/main/java/org/jabref/logic/importer/fetcher/ISIDOREFetcher.java

@@ -8,14 +8,12 @@
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;
-import java.util.Optional;
 import java.util.StringJoiner;
 
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
 import javax.xml.parsers.ParserConfigurationException;
 
-import org.jabref.logic.help.HelpFile;
 import org.jabref.logic.importer.FetcherException;
 import org.jabref.logic.importer.PagedSearchBasedParserFetcher;
 import org.jabref.logic.importer.Parser;