Merge pull request #391 from zan-mateusz/fix/winrm-pct-limitation

add a winrm limitation section for using % character in env vars

guide/blueprints/winrm/limitations.md

diff --git a/guide/blueprints/winrm/limitations.md b/guide/blueprints/winrm/limitations.md
index 6d48049..124be7c 100644
--- a/guide/blueprints/winrm/limitations.md
+++ b/guide/blueprints/winrm/limitations.md
@@ -98,6 +98,10 @@
 Note this is not done automatically because that could affect the capture and returning
 of the exit code for the commands executed.
 
+### Usage of '%' in Environment Variables
+
+WinRM does not support the `%` character in the value of any environment variable passed to it.  It attempts to treat it as a reference to a system variable, and will refuse the command if that character is used in a way inconsistent with such a reference.  All other characters are supported and there is no way to escape a single `%`, so it is recommended to ensure that character is not used in values passed as WinRM environment variables.
+
 ### Install location
 
 Work is required to better configure a default install location on the VM (e.g. so that