Unify TODO comment style for better searchability

[ChrisThrasher]

Description

Continuing precedent set in #2825

[ChrisThrasher]

SFML/src/SFML/Window/iOS/JoystickImpl.mm

Lines 34 to 37 in 5da2864

	void JoystickImpl::initialize()
	{
	// Not implemented
	}

I found some more functions that might need TODO statements since they lack an implementation but in theory could be implemented.

[coveralls]

Pull Request Test Coverage Report for Build 8857586167

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 51.624%

---

Totals
Change from base Build 8841003784:	0.0%
Covered Lines:	10367
Relevant Lines:	18964

---

💛 - Coveralls