checker: check fn return void fn call (no value) (fix #22389)

[yuyi98]

This PR check fn return void fn call (no value) (fix #22389).

• Check fn return void fn call (no value).
• Fix return match expr with result.
• Add tests.

fn main() {
	install_command(['github:some/thing'], 1) or { panic(err) }
}

pub fn install_command(args []string, verbosity int) ! {
	if args.len == 0 {
		return error('${@FN} requires an argument')
	}
	component := args[0]
	if component.count(':') == 0 {
		return install_command(['github:${component}'], verbosity)
	}
	source := component.all_before(':')
	if source != 'github' {
		return error('${@FN} unknown source `${source}`')
	}
	unit := component.all_after(':')
	return match source {
		'github' {
			install_from_github(unit, verbosity)!
		}
		else {
			error('${@FN} unknown source `${source}`')
		}
	}
}

fn install_from_github(unit string, verbosity int) ! {
	dump(unit)
}

PS D:\Test\v\tt1> v run .    
tt1.v:20:4: error: `install_from_github(unit, verbosity)!` used as value
   18 |     return match source {
   19 |         'github' {
   20 |             install_from_github(unit, verbosity)!
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   21 |         }
   22 |         else {

fn main() {
	install_command(['github:some/thing'], 1) or { panic(err) }
}

pub fn install_command(args []string, verbosity int) ! {
	if args.len == 0 {
		return error('${@FN} requires an argument')
	}
	component := args[0]
	if component.count(':') == 0 {
		return install_command(['github:${component}'], verbosity)
	}
	source := component.all_before(':')
	if source != 'github' {
		return error('${@FN} unknown source `${source}`')
	}
	unit := component.all_after(':')
	return match source {
		'github' {
			install_from_github(unit, verbosity)
		}
		else {
			error('${@FN} unknown source `${source}`')
		}
	}
}

fn install_from_github(unit string, verbosity int) ! {
	dump(unit)
}

PS D:\Test\v\tt1> v run .    
[.\\tt1.v:29] unit: some/thing

[spytheman]

Excellent work.