code: @Nonnull
      public BugInstance addUnknownSourceLine(String className, String sourceFile) {
          SourceLineAnnotation sourceLineAnnotation = SourceLineAnnotation.createUnknown(className, sourceFile);
          if (sourceLineAnnotation != null) {
              add(sourceLineAnnotation);
          }
          return this;
      }
docs: Add a non-specific source line annotation. This will result in the entire
  source file being displayed.
  
  @param className
  the class name
  @param sourceFile
  the source file name
  @return this object