fix: use UTF-8 as default encoding for files ~ resolves #5133

If we create journal abbrev files via the JabRef, they are saved in UTF-8.
So it makes sense to use this as default encoding. Also see #5133.

src/main/java/org/jabref/logic/journals/AbbreviationParser.java

@@ -39,7 +39,8 @@ public void readJournalListFromResource(String resourceFileName) {
     }
 
     public void readJournalListFromFile(File file) throws FileNotFoundException {
-        try (FileReader reader = new FileReader(Objects.requireNonNull(file))) {
+        try (FileInputStream stream = new FileInputStream(Objects.requireNonNull(file));
+             InputStreamReader reader = new InputStreamReader(stream, Objects.requireNonNull(StandardCharsets.UTF_8))) {
             readJournalList(reader);
         } catch (FileNotFoundException e) {
             throw e;

src/main/java/org/jabref/logic/journals/JournalAbbreviationLoader.java

@@ -11,7 +11,6 @@
 import org.slf4j.LoggerFactory;
 
 public class JournalAbbreviationLoader {
-
     private static final Logger LOGGER = LoggerFactory.getLogger(JournalAbbreviationLoader.class);
 
     // journal initialization