[PATH] dev-manual: mention that "bmap-tools" is transitional package

For modern Debian and Ubuntu releases, mention that the "bmap-tools"
package is transitional to the newer "bmaptool" package.

Signed-off-by: Robert P. J. Day <[email protected]>

---

  someone can decide if this is worth adding to the bmaptool section;
i can go either way.

diff --git a/documentation/dev-manual/bmaptool.rst b/documentation/dev-manual/bmaptool.rst
index 87162a49c..1e5ad2bba 100644
--- a/documentation/dev-manual/bmaptool.rst
+++ b/documentation/dev-manual/bmaptool.rst
@@ -24,6 +24,12 @@ system image files much faster.

          $ bitbake bmaptool-native -caddto_recipe_sysroot

+   -  Finally, in modern Ubuntu and Debian releases, the ``bmap-tools``
+      package is a transitional package; it exists solely to ensure
+      backward compatibility and smooth upgrades from older installations.
+      You can safely remove it and install the active package, ``bmaptool``,
+      which contains the actual utilities for flashing block images.
+
 Following, is an example that shows how to flash a Wic image. Realize
 that while this example uses a Wic image, you can use `bmaptool` to flash
 any type of image. Use these steps to flash an image using `bmaptool`: