- ignore leftover XML files e.g. from other branches
- tested manually in MVC repo with a bad doc file outside a K project
- limit checked XML files to those in `bin` directory under K projects
- align with clean target: that only removes bin directories under K projects
- approach ignores XML files in .csproj projects but no such projects in
repos where _k-xml-docs-test.shade file is used
Address old [comment](https://github.com/aspnet/Universe/pull/101/files#r16633938) from @Eilon on PR#101
> Traditionally we use i++ and not ++i.
- can't be done as a unit test because `k.cmd test` doesn't write assemblies for referenced projects
- instead support extending the "test" target in builds
To enable this in a repo, add the following to the makefile.shade file:
```
#xml-docs-test target='test'
k-xml-docs-test
```
Example output with one syntax error and one invalid reference:
```
info: Target xml-docs-test
warn: Invalid documentation syntax in src\Microsoft.AspNet.Mvc.Core\bin\debug\net45\Microsoft.AspNet.Mvc.Core.xml
warn: 3170: <!-- Badly formed XML comment ignored for member "T:Microsoft.AspNet.Mvc.Rendering.HtmlHelper" -->
warn: 3203: If the object is already an <see cref="!:IDictionaries<string, object>"/> instance, then it is
```