Docs: clarify wording of resize background option

docs/api-resize.md

@@ -46,7 +46,7 @@ Possible interpolation kernels are:
     *   `options.height` **[String][10]?** alternative means of specifying `height`. If both are present this take priority.
     *   `options.fit` **[String][10]** how the image should be resized to fit both provided dimensions, one of `cover`, `contain`, `fill`, `inside` or `outside`. (optional, default `'cover'`)
     *   `options.position` **[String][10]** position, gravity or strategy to use when `fit` is `cover` or `contain`. (optional, default `'centre'`)
-    *   `options.background` **([String][10] | [Object][9])** background colour when using a `fit` of `contain`, parsed by the [color][11] module, defaults to black without transparency. (optional, default `{r:0,g:0,b:0,alpha:1}`)
+    *   `options.background` **([String][10] | [Object][9])** background colour when `fit` is `contain`, parsed by the [color][11] module, defaults to black without transparency. (optional, default `{r:0,g:0,b:0,alpha:1}`)
     *   `options.kernel` **[String][10]** the kernel to use for image reduction. (optional, default `'lanczos3'`)
     *   `options.withoutEnlargement` **[Boolean][12]** do not enlarge if the width *or* height are already less than the specified dimensions, equivalent to GraphicsMagick's `>` geometry option. (optional, default `false`)
     *   `options.withoutReduction` **[Boolean][12]** do not reduce if the width *or* height are already greater than the specified dimensions, equivalent to GraphicsMagick's `<` geometry option. (optional, default `false`)

lib/resize.js

@@ -211,7 +211,7 @@ function isRotationExpected (options) {
  * @param {String} [options.height] - alternative means of specifying `height`. If both are present this take priority.
  * @param {String} [options.fit='cover'] - how the image should be resized to fit both provided dimensions, one of `cover`, `contain`, `fill`, `inside` or `outside`.
  * @param {String} [options.position='centre'] - position, gravity or strategy to use when `fit` is `cover` or `contain`.
- * @param {String|Object} [options.background={r: 0, g: 0, b: 0, alpha: 1}] - background colour when using a `fit` of `contain`, parsed by the [color](https://www.npmjs.org/package/color) module, defaults to black without transparency.
+ * @param {String|Object} [options.background={r: 0, g: 0, b: 0, alpha: 1}] - background colour when `fit` is `contain`, parsed by the [color](https://www.npmjs.org/package/color) module, defaults to black without transparency.
  * @param {String} [options.kernel='lanczos3'] - the kernel to use for image reduction.
  * @param {Boolean} [options.withoutEnlargement=false] - do not enlarge if the width *or* height are already less than the specified dimensions, equivalent to GraphicsMagick's `>` geometry option.
  * @param {Boolean} [options.withoutReduction=false] - do not reduce if the width *or* height are already greater than the specified dimensions, equivalent to GraphicsMagick's `<` geometry option.