[docs][en] formats

Author: Jinjiang

docs/en/guides/testing-SFCs-with-karma.md

@@ -29,7 +29,7 @@ Next we need to define a test script in our `package.json`.
 
 ### Karma Configuration
 
-Create a karma.conf.js file in the index of the project:
+Create a `karma.conf.js` file in the index of the project:
 
 ```js
 // karma.conf.js
@@ -138,7 +138,7 @@ Install `karma-coverage`, `babel-plugin-istanbul`, and `cross-env`:
 npm install --save-dev karma-coverage cross-env
 ```
 
-We're going to use `cross-env` to set a `BABEL_ENV` environment variable. This way we can use babel-plugin-istanbul when we're compiling for our tests—we don't want to include `babel-plugin-istnabul` when we compile our production code:
+We're going to use `cross-env` to set a `BABEL_ENV` environment variable. This way we can use `babel-plugin-istanbul` when we're compiling for our tests—we don't want to include `babel-plugin-istnabul` when we compile our production code:
 
 ```
 npm install --save-dev babel-plugin-istanbul
@@ -160,7 +160,7 @@ Update your `.babelrc` file to use `babel-plugin-istanbul` when `BABEL_ENV` is s
 }
 ```
 
-Now update the karma.conf.js file to use coverage. Add `coverage` to the reporters array, and add a coverageReporter field:
+Now update the `karma.conf.js` file to use coverage. Add `coverage` to the `reporters` array, and add a `coverageReporter` field:
 
 ```js
 // karma.conf.js

docs/en/guides/using-with-vuex.md

@@ -290,7 +290,7 @@ Getters, mutations, and actions are all JavaScript functions, so we can test the
 
 The benefit to testing getters, mutations, and actions separately is that your unit tests are detailed. When they fail, you know exactly what is wrong with your code. The downside is that you will need to mock Vuex funtions, like `commit` and `dispatch`. This can lead to a situation where your unit tests pass, but your production code fails because your mocks are incorrect.
 
-We'll create two test files, mutations.spec.js and getters.spec.js:
+We'll create two test files, `mutations.spec.js` and `getters.spec.js`:
 
 First, let's test the `increment` mutations:
 
@@ -339,7 +339,7 @@ The benefit of testing creating a running store instance is we don't have to moc
 
 The downside is that when a test breaks, it can be difficult to find where the problem is.
 
-Let's write a test. When we create a store, we'll use `localVue` to avoid polluting the Vue base constructor. The test creates a store using the store-config.js export:
+Let's write a test. When we create a store, we'll use `localVue` to avoid polluting the Vue base constructor. The test creates a store using the `store-config.js` export:
 
 ```js
 import mutations from './mutations'