Fix Issue 23636 - No spec docs for shared qualifer

[ntrel]

No description provided.

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	23636	enhancement	No spec docs for shared qualifer

[anon17]

Additions:

Mutable data that is meant to be shared among multiple threads should be declared with the shared qualifier. This prevents unsynchronized reading and writing to the data, which would otherwise cause data races. It's done by differentiating between shared and unshared data, so they can't implicitly substitute each other without a cast, and thus shared data can't be accidentally treated as unshared. The shared type attribute is transitive (like const and immutable).

Lastly, to declare global/static data to be implicitly shared across multiple threads without any compiler checks, see $(DDSUBLINK spec/attribute, gshared, __gshared). Such data has unshared type.

[RazvanN7]

@anon17 feel free to submit a PR.