[eclipse-cdt#120] Clangd options in preference/project properties not…

… changeable

Set preference store for Properties page when context element is alreayd
known
Correct metadata for query driver preference

bundles/org.eclipse.cdt.lsp.clangd/src/org/eclipse/cdt/lsp/internal/clangd/ClangdMetadataDefaults.java

@@ -83,7 +83,7 @@ public PreferenceMetadata<Boolean> prettyPrint() {
 	@Override
 	public PreferenceMetadata<String> queryDriver() {
 		return new PreferenceMetadata<>(String.class, //
-				"pretty_print", //$NON-NLS-1$
+				"query_driver", //$NON-NLS-1$
 				Optional.ofNullable(PathUtil.findProgramLocation("gcc", null)) //$NON-NLS-1$
 						.map(p -> p.removeLastSegments(1).append(IPath.SEPARATOR + "*"))// //$NON-NLS-1$
 						.map(IPath::toString)//

bundles/org.eclipse.cdt.lsp.clangd/src/org/eclipse/cdt/lsp/internal/clangd/editor/properties/LspEditorPropertiesPage.java

@@ -48,11 +48,12 @@ public LspEditorPropertiesPage() {
 
 	@Override
 	protected Control createContents(Composite parent) {
+		setPreferenceStore(store());
 		Composite composite = new Composite(parent, SWT.NONE);
 		composite.setLayout(GridLayoutFactory.fillDefaults().numColumns(3).create());
 		composite.setLayoutData(GridDataFactory.fillDefaults().grab(true, false).create());
 		area = new ClangdConfigurationArea(composite, configuration.metadata());
-		area.init(store(), this);
+		area.init(getPreferenceStore(), this);
 		area.fields().forEach(FieldEditor::load);
 		return composite;
 	}