Update transformations.md

Author: mayashavin

docs/url-docs/content/en/usage/transformations.md

@@ -446,7 +446,7 @@ const url = buildImageUrl('non-exist', {
 
 ### `density`
 
-* Type: `String`
+* Type: `Number`
 
 To define the density when converting a vector file to image format.
 
@@ -636,4 +636,4 @@ const url = buildImageUrl('woman-sample', {
 
 ### `fallbackContent`
 
-### `ocr` -->
+### `ocr` -->