Add support for inferring property types on templates

[cwhite92]

With the following style of return:

return ['id' => $plainPhpObject->id];

scramble is generating documentation that says id is a string:

despite id being type hinted to an integer:

from dumping out in one of my extensions, I can see the following comment on the property inference:

Cannot infer type of property [id] fetch on template type: not supported yet.

After asking in Discord, it was suggested I make a GitHub issue.

Cheers!