Improve grammar and formatting in docs

Author: acjh

doc/WebSite/Module-System.md

@@ -22,7 +22,7 @@ applications. The simplest module definition can be as shown below:
         }
     }
 
-The Module definition class is responsible for registering it's classes via
+The Module definition class is responsible for registering its classes via
 [dependency injection](Dependency-Injection.md), if needed (it can be done
 conventionally as shown above). It can also configure the application
 and other modules, add new features to the application, and so on...
@@ -138,7 +138,7 @@ overriding the **Application\_Start** in the **global.asax** as shown below:
 ##### Controllers in PlugIns
 
 If your modules include MVC or Web API Controllers,
-ASP.NET can not investigate your controllers. To overcome this issue,
+ASP.NET cannot investigate your controllers. To overcome this issue,
 you can change the global.asax file like below:
 
     using System.Web;

doc/WebSite/Plugin.md

@@ -39,7 +39,7 @@ namespace DatabaseMaintainer
 }
 ```
 
-- Add a background worker 
+- Add a background worker
 
 ````c#
 using System;
@@ -82,21 +82,23 @@ namespace DatabaseMaintainer
 }
 ````
 
-Project solution looks like following:
+Project solution looks like the following:
 
 <img src="images/plugin-solution.png" alt="plugin-solution" class="img-thumbnail" />
 
 #### Build the Plugin
 
-Build project in release mode. `DatabaseMaintainer.dll` will be created in folder 
+Build project in release mode. `DatabaseMaintainer.dll` will be created in the folder
 `DatabaseMaintainer\DatabaseMaintainer\bin\Release\netcoreapp2.1`.
 
 ### Add Plugin to the Application
 
-Following example, it will be loaded from `wwwroot` folder. You can change plugins folder location.
-First following line should be added to application `Startup.cs` that you want to add to application (MVC or Host). 
+In the following example, it will be loaded from the `wwwroot` folder. You can change the plugins folder location.
+First, the following line should be added to the `Startup.cs` of the application (MVC or Host) that you want to add the plugin to.
 
-`options.PlugInSources.AddFolder(Path.Combine(_hostingEnvironment.WebRootPath, "Plugins"), SearchOption.AllDirectories);`
+```c#
+options.PlugInSources.AddFolder(Path.Combine(_hostingEnvironment.WebRootPath, "Plugins"), SearchOption.AllDirectories);
+```
 
 Latest Startup.cs  
 
@@ -124,7 +126,9 @@ public class Startup
             options.PlugInSources.AddFolder(Path.Combine(_hostingEnvironment.WebRootPath, "Plugins"), SearchOption.AllDirectories);
         );
     }
-...
+
+    ...
+}
 ```
 
 And copy `DatabaseMaintainer.dll` from plugin to application `.Mvc/wwwroot/Plugins` folder.
@@ -133,6 +137,6 @@ And copy `DatabaseMaintainer.dll` from plugin to application `.Mvc/wwwroot/Plugi
 
 ### Run the Application
 
-Run project and see Logs.txt to check if it works.
+Run the project and see Logs.txt to check if it works.
 
 <img src="images/plugin-log.png" alt="plugin-log" class="img-thumbnail" />