Recognize incomplete Prism hash literals

[OskarEichler]

Summary

Treat Prism's missing-closing-brace diagnostic as an incomplete expression so source extraction continues reading the following lines.

Reproduction and fix

On Ruby 4, an input such as {audit: raises expected a } to close the hash literal; the current diagnostic list treats that as hard-invalid. Add the precise Prism message to the incomplete-expression patterns.

Regression coverage

• added a multiline hash-literal extraction case
• 24-case incomplete/hard-invalid parser matrix passes on Ruby 4.0.6 and 3.2.11
• final composition: 41 examples / 0 failures on both Rubies
• syntax, diff check, exact packaging and Rails integration pass