Standardise punctuation in workingwithtw/

Make the use of punctuation and bold text conform to the tw.com Documentation Style Guide.

This includes placing unrelated commas and full stops outside of quotation marks, and replacing single quotes with the double quotes that seem to be the standard on tw.com.

It also includes using bold for names of example tiddlers and tags that are mentioned in the discussion but are not actually present in tw.com. These would be downright misleading if they were links.