Update README.md

[leapoli]

There is a mistake when the README.md says:

• infoTextFiltered, defaults to '<span class="label label-warning">Filtered</span> {0} from {1}', determines which element format to use when some element is filtered. Remember to insert the {0} and {1} placeholders.

Should say instead (that's the real code that's inserted into the span class):

• infoTextFiltered, defaults to '<span class="badge badge-warning">Filtered</span> {0} from {1}', determines which element format to use when some element is filtered. Remember to insert the {0} and {1} placeholders.