Fix Issues 16082 and 16086

[RazvanN7]

Look for aliasthis before checking upper scopes.

[dlang-bot]

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	16082	normal	Can't access alias this member with same name as module
✓	16086	normal	Imported function name shadows alias this member

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub fetch digger
dub run digger -- build "master + dmd#8885"

[RazvanN7]

@WalterBright Is this solution better?

[patrickkh7788]

can you take a look at this maybe related: https://issues.dlang.org/show_bug.cgi?id=19327