framework->config->allow_whitespace(true) consistenly produces inappropriate behaviour

[thinkier]

The bug happens because of incorrect prefix detection, just when whitespaces are enabled.

client.with_framework(StandardFramework::new()
	.configure(|c| c
		.allow_whitespace(true)
	)
	// ...

In the following reproduction table the following should be assumed.

• The prefix is $c
• There are 2 commands.
  • One has the name p and the other has the name h

Command Sent By User	Command Triggered	Is it correct
$cp	p	✅
$ch	h	✅
$chp	p	❌
$chh	h	❌🤔
$cah	h	❌
$cap	p	❌
$ca h	h	❌
$caah	None	✅
$c ah	None	✅

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Side bug: also found that config.allow_whitespace(false) may not be respected.

---

Edits:

• Pressed Ctrl+Enter accidentally.
• Found another bug relating to the same code.

[thinkier]

This is fixed and merged, can close now...