tools: binman: minor formatting fix in docs

This should fix a rendering oddity when viewing the docs online at
https://u-boot.readthedocs.io/en/latest/develop/package/binman.html

Signed-off-by: Ralph Siemsen <ralph.siemsen@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/binman/binman.rst b/tools/binman/binman.rst
index 03a99a1..0921e31 100644
--- a/tools/binman/binman.rst
+++ b/tools/binman/binman.rst
@@ -393,9 +393,9 @@
 Running binman
 --------------
 
-Type::
+Type:
 
-.. code-block: bash
+.. code-block:: bash
 
    make NO_PYTHON=1 PREFIX=/ install
     binman build -b <board_name>