update monaco.d.ts

src/vs/monaco.d.ts

@@ -5058,6 +5058,18 @@ declare namespace monaco.languages {
 		provideDefinition(model: editor.ITextModel, position: Position, token: CancellationToken): ProviderResult<Definition | DefinitionLink[]>;
 	}
 
+	/**
+	 * The definition provider interface defines the contract between extensions and
+	 * the [go to definition](https://code.visualstudio.com/docs/editor/editingevolved#_go-to-definition)
+	 * and peek definition features.
+	 */
+	export interface DeclarationProvider {
+		/**
+		 * Provide the declaration of the symbol at the given position and document.
+		 */
+		provideDeclaration(model: editor.ITextModel, position: Position, token: CancellationToken): ProviderResult<Definition | DefinitionLink[]>;
+	}
+
 	/**
 	 * The implementation provider interface defines the contract between extensions and
 	 * the go to implementation feature.