Replace TextPlacement enum with typedef

src/ol/render/canvas.js

@@ -61,7 +61,7 @@ import {getFontParameters} from '../css.js';
  * @property {string} [textAlign] TextAlign.
  * @property {string} [justify] Justify.
  * @property {string} textBaseline TextBaseline.
- * @property {string} [placement] Placement.
+ * @property {import('../style/Text.js').TextPlacement} [placement] Placement.
  * @property {number} [maxAngle] MaxAngle.
  * @property {boolean} [overflow] Overflow.
  * @property {import("../style/Fill.js").default} [backgroundFill] BackgroundFill.

src/ol/render/canvas/TextBuilder.js

@@ -3,7 +3,6 @@
  */
 import CanvasBuilder from './Builder.js';
 import CanvasInstruction from './Instruction.js';
-import TextPlacement from '../../style/TextPlacement.js';
 import {asColorLike} from '../../colorlike.js';
 import {
   defaultFillStyle,
@@ -177,7 +176,7 @@ class CanvasTextBuilder extends CanvasBuilder {
     let stride = geometry.getStride();
 
     if (
-      textState.placement === TextPlacement.LINE &&
+      textState.placement === 'line' &&
       (geometryType == 'LineString' ||
         geometryType == 'MultiLineString' ||
         geometryType == 'Polygon' ||