docs: fix alignment of "code blocks"

We provide a lot of variable examples as code blocks in the following
format:

	some text: `Variable`

or
	some test:
	`Variable`

Which is not as pretty as (when converted to html/pdf):

	some text:

		Variable

Converted all and hoppefully this will improve readability a bit.

Signed-off-by: Mirza Krak <mirza.krak@endian.se>

docs/contributing.md

@@ -20,10 +20,12 @@ To contribute to this project you should send pull requests to the github mirror
 the patches for review to the above specified mailing list.
 
 When creating patches for the mailing list, please use something like:
-`git format-patch -s --subject-prefix='meta-raspberrypi][PATCH' origin`
+
+    git format-patch -s --subject-prefix='meta-raspberrypi][PATCH' origin
 
 When sending patches to the mailing list, please use something like:
-`git send-email --to yocto@yoctoproject.org <generated patch>`
+
+    git send-email --to yocto@yoctoproject.org <generated patch>
 
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