Improve Diffable output

A space separator between kind="" and indent="" has been missing. File
was still parsable, but is easier to read when adding it back.

biblemulticonverter/src/main/java/biblemulticonverter/format/Diffable.java

@@ -528,7 +528,7 @@ public void visitLineBreak(ExtendedLineBreakKind kind, int indent) throws IOExce
 			} else if (indent == 0) {
 				w.write("<br kind=\"" + kind.name() + "\"/>");
 			} else {
-				w.write("<br kind=\"" + kind.name() + "\"indent=\"" + indent + "\"/>");
+				w.write("<br kind=\"" + kind.name() + "\" indent=\"" + indent + "\"/>");
 			}
 			if (linePrefix != null)
 				startNewLine = true;