Fix Issue 15103 - Improve declaration / initialization syntax error message

[adelavais]

No description provided.

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	15103	minor	Improve declaration / initialization syntax error message

Testing this PR locally

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

dub run digger -- build "master + dmd#11477"

[MoonlightSentinel]

Thanks for your PR.

[RazvanN7]

Please squash the commits and address Nils's comment and we are good to go.

[adelavais]

Please squash the commits and address Nils's comment and we are good to go.

The above is my attempt to squash. Sorry about that. Will redo.

Addressed