Fix quotation marks

src/objects/Line.d.ts

@@ -15,7 +15,7 @@ export class Line extends Object3D {
   geometry: Geometry | BufferGeometry;
   material: Material | Material[];
 
-  type: "Line" | "LineLoop" | "LineSegments";
+  type: 'Line' | 'LineLoop' | 'LineSegments';
   isLine: true;
 
   computeLineDistances(): this;

src/objects/LineLoop.d.ts

@@ -9,6 +9,6 @@ export class LineLoop extends Line {
     material?: Material | Material[]
   );
 
-  type: "LineLoop";
+  type: 'LineLoop';
   isLineLoop: true;
 }

src/objects/LineSegments.d.ts

@@ -19,6 +19,6 @@ export class LineSegments extends Line {
     mode?: number
   );
 
-  type: "LineSegments";
+  type: 'LineSegments';
   isLineSegments: true;
 }