Add preference option for non-buffered file handling in Xtext editors.

[raghucssit]

see #1500

[Copilot]

Pull request overview

Adds a UI preference to control “non-buffered file handling” so LSP4E can better support editors (e.g., Xtext) whose IDocument is not backed by Eclipse file buffers, aligning with #1500.

Changes:

• Added a new translatable UI label for the preference.
• Exposed a new checkbox on the Language Server preference page backed by org.eclipse.lsp4e.resourceFallback.enabled.
• Persisted the checkbox value to the plugin preference store on OK.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
org.eclipse.lsp4e/src/org/eclipse/lsp4e/ui/messages.properties	Adds the UI string for the new preference checkbox.
org.eclipse.lsp4e/src/org/eclipse/lsp4e/ui/Messages.java	Exposes the new message key to the NLS bundle.
org.eclipse.lsp4e/src/org/eclipse/lsp4e/ui/LanguageServerPreferencePage.java	Adds the checkbox and saves/loads the preference value.

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[rubenporras]

Hi @raghucssit ,

I think the end user should not be interested in such flag. Could we instead enable it in the Activator of CoPilot plugin?