GSP: "flash" object calls stay coloured despite being commented

**171.3566**
**test.gsp:**
```

${flash.message} Use block comment here

```
_⚠️ attachment `flash.jpg` was not included in the export_

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*1 attachment(s) referenced here (`flash.jpg`) are not part of the CSV export.*
*Imported from [IDEA-168533](https://youtrack.jetbrains.com/issue/IDEA-168533) · Type: Bug · Votes: 0*
*Comments, attachments, dates and reporter are not part of the export — follow the link above for the full history.*

Open test.gsp in IntelliJ and reproduce the highlighting around ${flash.message} inside the commented section. Use the reported behavior and the referenced flash.jpg, which is unavailable here, to compare the current rendering; done when the flash object call is no longer colored as active code when commented.

Written by the indexing model from the issue text.