Minor Grammer fixes to docs (#3521)

Author: jeffin143

src/content/guides/installation.md

@@ -68,7 +68,7 @@ If you are enthusiastic about using the latest that webpack has to offer, you ca
 
 ``` bash
 npm install --save-dev webpack@next
-# or specific tag/branch
+# or a specific tag/branch
 npm install --save-dev webpack/webpack#<tagname/branchname>
 ```
 

src/content/guides/progressive-web-application.md

@@ -111,7 +111,7 @@ precache-manifest.b5ca1c555e832d6fbf9462efd29d27eb.js  268 bytes          [emitt
 ...
 ```
 
-As you can see, we now have 2 extra files being generated; `service-worker.js` and the more verbose `precache-manifest.b5ca1c555e832d6fbf9462efd29d27eb.js`. `service-worker.js` is the Service Worker file and `precache-manifest.b5ca1c555e832d6fbf9462efd29d27eb.js` is a file that `service-worker.js` requires so it can run. Your own generated files will likely be different; but you should have an `service-worker.js` file there.
+As you can see, we now have 2 extra files being generated; `service-worker.js` and the more verbose `precache-manifest.b5ca1c555e832d6fbf9462efd29d27eb.js`. `service-worker.js` is the Service Worker file and `precache-manifest.b5ca1c555e832d6fbf9462efd29d27eb.js` is a file that `service-worker.js` requires so it can run. Your own generated files will likely be different; but you should have a `service-worker.js` file there.
 
 So we're now at the happy point of having produced a Service Worker. What's next?
 

src/content/plugins/ignore-plugin.md

@@ -9,7 +9,7 @@ contributors:
   - iamakulov
 ---
 
-IgnorePlugin prevents generation of modules for `import` or `require` calls matching the regular expressions or filter functions:
+IgnorePlugin prevents the generation of modules for `import` or `require` calls matching the regular expressions or filter functions:
 
 ## Using regular expressions