Add property typehints in Internal directory

[jack-worman]

Added more property typehints but just for in the Internal directory to ensure BC.

I then used php-cs-fixer to clean up redundant phpdocs.

[weirdan]

@jack-worman would you mind running benchmarks against this PR and the master branch? It looks like it could have more performance impact than your previous PR.

[jack-worman]

@jack-worman would you mind running benchmarks against this PR and the master branch? It looks like it could have more performance impact than your previous PR.

OLD (5.2.0):
256.11s user 20.99s system 342% cpu 1:20.90 total
251.93s user 19.63s system 351% cpu 1:17.33 total
252.73s user 19.57s system 347% cpu 1:18.33 total
254.36s user 19.10s system 350% cpu 1:17.92 total
252.01s user 19.30s system 352% cpu 1:16.94 total
247.46s user 18.03s system 340% cpu 1:17.97 total

NEW (this branch):
246.72s user 19.21s system 346% cpu 1:16.84 total
243.94s user 18.63s system 354% cpu 1:14.13 total
244.22s user 18.06s system 357% cpu 1:13.39 total
249.78s user 19.64s system 346% cpu 1:17.82 total
260.73s user 21.50s system 336% cpu 1:23.89 total
255.39s user 19.22s system 354% cpu 1:17.42 total

Using eyeball statistics, I would say there is no performance difference.
I ran this on my jobs fairly large codebase.

[weirdan]

LGTM.

@orklah, @danog any objections?

[orklah]

Should we ignore backward compatibiliy checks here?

[jack-worman]

Should we ignore backward compatibiliy checks here?

Those BC breaks are because those files were missing their @internal annotation, even though they were in the Psalm\Internal namespace.

[danog]

If there are no performance impacts (and according to your tests performance improved even, were you using opcache? If yes, the typehints might've triggered some optimizations), LGTM!

[orklah]

Thanks!