Arg-less ./pants tailor deprecation warning confusing for users new to Pants

[danxmoran]

Describe the bug

# Create some new source dir
mkdir  src/new_dir
# Create a new file in that dir
echo 'print "hey" > src/new_dir/new_file.py'
# Tailor the file
./pants tailor

The above will print:

Currently, `./pants tailor` without arguments will run against every file in the project.

In Pants 2.14, you must use CLI arguments. Use:

  * `::` to run on everything
  * `dir::` to run on `dir` and subdirs
  * `dir` to run on `dir`

I've gotten feedback from users ~relatively unfamiliar with Pants that they aren't sure what to do about the warning.

I think having something more copy-paste-able might help. Something like:

Currently, `./pants tailor` without arguments will run against every file in the project.

In Pants 2.14, you must use CLI arguments. Use:

  * `./pants tailor ::` to run on everything
  * `./pants tailor dir::` to run on `dir` and subdirs
  * `./pants tailor dir` to run on `dir`

Pants version

PANTS_SHA=19fe4e3cec21067791dea8f1351c033c7132f579

OS

Both

[Eric-Arellano]

Great suggestion! Thanks!