Merge pull request #459 from kalcifer/minor/nosources

Adds a line about nosources

Author: bebraw

content/configuration/devtool.md

@@ -24,6 +24,7 @@ Choose a style of [source mapping](http://blog.teamtreehouse.com/introduction-so
  cheap-module-source-map      | o     | -       | yes        | original source (lines only)
  eval-source-map              | --    | +       | no         | original source
  source-map                   | --    | --      | yes        | original source
+ nosources-source-map         | --    | --      | yes        | without source content
 
 Some of these values are suited for development and some for production. For development you typically want very fast Source Maps at the cost of bundle size, but for production you want separate Source Maps that are accurate.
 
@@ -49,6 +50,8 @@ W> There are some issues with Source Maps in Chrome. [We need your help!](https:
 
 `cheap-module-source-map` - A SourceMap without column-mappings that simplifies loaded Source Maps to a single mapping per line.
 
+`nosources-source-map` - A SourceMap is created without the `sourcesContent` in it. It can be used to map stack traces on the client without exposing all of the source code.
+
 T> See [`output.sourceMapFilename`](/configuration/output#output-sourcemapfilename) to customize the filenames of generated Source Maps.
 
 ?> This page needs more information to make it easier for users to choose a good option.