Added missing return on F_GetTradeRestriction

[sigtus]

Pull Request Prelude

• I have followed proper Hercules code styling.
• I have read and understood the contribution guidelines before making this PR.
• I am aware that this PR may be closed if the above-mentioned criteria are not fulfilled.

Changes Proposed

Added missing return on F_GetTradeRestriction. The function only created a variable but didn't return its value.

Issues addressed: none

[HerculesWSAPI]

This change is 

[AnnieRuru]

not really your fault but, can you also remove all those curly brackets ?
https://github.com/HerculesWS/Hercules/wiki/Coding-Style#chapter-3-placing-braces-and-spaces

Do not unnecessarily use braces where a single statement will do.

	if (condition)
		action();

and

	if (condition)
		do_this();
	else
		do_that();

yup, tested working with

prontera,157,188,5	script	test gname2	1_F_MARIA,{
	dispbottom F_GetTradeRestriction(512);
	dispbottom F_GetTradeRestriction(12333);
	end;
}