`grunt.file` documents unreleased feature: grunt.file.copy options "process"

[JKVeganAbroad]

Originally report: Issue # 1440 (gruntjs/grunt)

grunt.file.md advises that for the grunt.file.copy function:

  // The source file contents, source file path, and destination file path 
  // are passed into this function, whose return value will be used as the
  // destination file's contents. If this function returns `false`, the file
  // copy will be aborted.
  process: processFunction,

In particular: "The ... destination file path [is] passed into this function"

As of the latest release of Grunt, 0.4.5, this is not true. The documentation needs to be corrected to remove this, or advise that it will be available in future releases.