[PATCH 1/1] doc: clarify usage of the IMAGE_TYPE variable

[Cedric Hombourger <Cedric_Hombourger@mentor.com>]

Documentation of the IMAGE_TYPE variable was misleading since it
claimed that the variable could hold a space separated list of
image types to be generated. The current image generation code
really assumes that a single type will be specified. Also update
the documentation to list "wic-img" as a provided IMAGE_TYPE.

Signed-off-by: Cedric Hombourger <Cedric_Hombourger@mentor.com>
---
 doc/user_manual.md | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/doc/user_manual.md b/doc/user_manual.md
index 427f83d..87fd77a 100644
--- a/doc/user_manual.md
+++ b/doc/user_manual.md
@@ -361,11 +361,12 @@ Please refer to `Add a Custom Application` section for more information about wr
 
 ## Image Type Selection
 
-Isar can generate various images types for specific machine. The `IMAGE_TYPE` variable contains the list of image types to generate. Currently, the following image types are provided:
+Isar can generate various images types for specific machine. The type of the image to be generated may be specified through the `IMAGE_TYPE` variable. Currently, the following image types are provided:
 
  - `ext4` - Raw ext4 filesystem image (default option for `qemuarm` machine).
  - `rpi-sdimg` - A complete, partitioned Raspberry Pi SD card image (default option for the `rpi` machine).
- 
+ - `wic-img` - A full disk image with user-specified partitions created and populated using the wic tool.
+
 ---
 
 ## Add a New Distro
@@ -485,10 +486,11 @@ IMAGE_TYPE = "my-image"
 
 ### Reference Classes
 
-Isar contains two image type classes that can be used as reference:
+Isar contains three image type classes that can be used as reference:
 
  - `ext4-img`
  - `rpi-sdimg`
+ - `wic-img`
 
 ---
 
-- 
2.11.0