Merge branch 'jk/fast-export-anonymize'

Sometimes users want to report a bug they experience on their repository, but they are not at liberty to share the contents of the repository. "fast-export" was taught an "--anonymize" option to replace blob contents, names of people and paths and log messages with bland and simple strings to help them. * jk/fast-export-anonymize: docs/fast-export: explain --anonymize more completely teach fast-export an --anonymize option