False positive inspection 'Invalid i18n property key'

What steps will reproduce the problem?
1. Create new Grails project
2. Add folder xxx to i18n with messages.properties file
3. Add key hello=xxx to locale file
4. Try to use locale key in index.gsp
```

```
What is the expected result?
Link to locale key in gsp page

What happens instead?
Invalid i18n property key inspection shows error mark

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*Imported from [IDEA-119631](https://youtrack.jetbrains.com/issue/IDEA-119631) · Type: Bug · Votes: 1*
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Reproduce the problem by creating a Grails project, adding an i18n folder with messages.properties and the hello=xxx key, then referencing it with in index.gsp. Start by locating the "Invalid i18n property key" inspection and its handling of Grails message bundles. Done means the valid key is linked without an error mark.

Written by the indexing model from the issue text.