improve english documentation

doc/workflow/web_editor.md

 # GitLab Web Editor
 
-In GitLab you can create new files and edit existing one using our web editor. 
-Its really useful if you dont have access to command line or you want to make a quick small fix.
-You can access to web editor in several ways depends on context. 
-Lets start from newly created project. 
-Click on `Add a file` button to start web editor for creating first file.
+In GitLab you can create new files and edit existing files using our web editor.
+This is especially useful if you don't have access to a command line or you just want to do a quick fix.
+You can easily access the web editor, depending on the context.
+Let's start from newly created project.
+
+Click on `Add a file`
+to create the first file and open it in the web editor.
 
 ![web editor 1](web_editor/empty_project.png)
 
-Fill in file name, content, commit message and press commit button.
-After this file will be saved to repository.
+Fill in a file name, some content, a commit message and press the commit button.
+The file will be saved to the repository.
 
 ![web editor 2](web_editor/new_file.png)
 
-You can edit any text file in repository by pressing edit button when browsing file.
+You can edit any text file in a repository by pressing the edit button, when
+viewing the file.
 
 ![web editor 3](web_editor/show_file.png)
 
-Edit of file is pretty same as creating new file. 
-Except you can see preview of your changes to file in separate tab
+Editing a file is almost the same as creating a new file,
+with as addition the ability to preview your changes in a separate tab.
 
 ![web editor 3](web_editor/edit_file.png)