Use rake -P to give all tasks, rather than just those with descriptions about completion-ruby HOT 2 CLOSED

This was the old behavior, changed in e96f4cb. The commit message says it used to return some bogus suggestions, but I don’t quite recall how that was triggered.

from completion-ruby.

Those "bogus suggestions" are probably just the file and directory tasks.
I don't really think a completion tool should be make assumptions on what tasks the user wants displayed.

# rakefile
OUTPUT_DIR = 'out'
OUTPUT_FILE = OUTPUT_DIR + '/output'
directory OUTPUT_DIR

file OUTPUT_FILE -> OUTPUT_DIR do
    touch(OUTPUT_FILE)
end

task :build -> OUTPUT_FILE

valid tasks:
rake out
rake out/output
rake build

from completion-ruby.