dev-cmd/bump-cask-pr: use FromContentLoader when relevant.

[MikeMcQuaid]

When loading from tmp_contents in bump-cask-pr we're always loading from the contents and not from a e.g. filename etc. As a result, skip the detection of the correct loader (as the regex can be a bit flaky) and instead use FromContentLoader directly.

[Bo98]

as the regex can be a bit flaky

Do you know which regex is the flaky one?

[MikeMcQuaid]

@Bo98 This:

brew/Library/Homebrew/cask/cask_loader.rb

Lines 58 to 66 in 138b7b2

	# Cache compiled regex
	@regex ||= begin
	token = /(?:"[^"]*"|'[^']*')/
	curly = /\(\s*#{token.source}\s*\)\s*\{.*\}/
	do_end = /\s+#{token.source}\s+do(?:\s*;\s*|\s+).*end/
	/\A\s*cask(?:#{curly.source}|#{do_end.source})\s*\Z/m
	end
	return unless content.match?(@regex)

Thanks for review!