manuals: suppress excess use of "following" word

To simplify the style, replace "Following is" and "Following are"
by "here is" and "here are", sounding more natural.

In some cases, also go further by simplifying "Here are/is xxx"
by "xxx are/is" when the "are" or "is" are not two far at
the end of the sentence.

In some cases too, completely remove the sentence, when
it's redundant with the preceding title.

(From yocto-docs rev: 2539f1b9cbf9bdd40eff93c6522dc76133debed7)

Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
CC: Daniel Ammann <daniel.ammann@bytesatwork.ch>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

documentation/dev-manual/runtime-testing.rst

@@ -199,7 +199,7 @@ perform a one-time setup of your controller image by doing the following:
    "controller" image and you can customize the image recipe as you would
    any other recipe.
 
-   Here are the image recipe requirements:
+   Image recipe requirements are:
 
    -  Inherits ``core-image`` so that kernel modules are installed.
 
@@ -578,7 +578,7 @@ data:
    When set to "true", the package is not automatically installed into
    the DUT.
 
-Following is an example JSON file that handles test "foo" installing
+Here is an example JSON file that handles test "foo" installing
 package "bar" and test "foobar" installing packages "foo" and "bar".
 Once the test is complete, the packages are removed from the DUT::