Documentation/distributions: Separate all vendors by exactly one blank line

Change-Id: Ib1718dfa174e2a4e9c2c4b5564e196e8483a8f3c
Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/54271
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by:  Felix Singer <felixsinger@posteo.net>
diff --git a/Documentation/distributions.md b/Documentation/distributions.md
index 75ac698..8401836 100644
--- a/Documentation/distributions.md
+++ b/Documentation/distributions.md
@@ -29,7 +29,6 @@
 [Libretrend](https://libretrend.com) sells the Librebox, a NUC-like PC which
 ships with coreboot firmware.
 
-
 ### PC Engines APUs
 
 [PC Engines](https://pcengines.ch) designs and sells embedded PC hardware that