docs-wide: update wic source plugin names

WIC plugins were renamed after commit 2de444fc3ef4 ("wic: plugins source
bootimage/isoimage rename to allow be imported") in OE-Core. They no
longer contain dashes, but underscores.

(From yocto-docs rev: 7224d7733e9e0f423475e1b9c5b48aff0de1f744)

Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/classes.rst

@@ -3265,7 +3265,7 @@ The variables used by this class are:
    :oe_git:`meta/conf/image-uefi.conf
    </openembedded-core/tree/meta/conf/image-uefi.conf>`
 -  :term:`IMAGE_EFI_BOOT_FILES`: files to install to EFI boot partition
-   created by the ``bootimg-efi`` Wic plugin
+   created by the ``bootimg_efi`` Wic plugin
 -  :term:`INITRAMFS_IMAGE`: initramfs recipe name
 -  :term:`KERNEL_DEVICETREE`: optional devicetree files to embed into UKI
 -  :term:`UKIFY_CMD`: `ukify

documentation/ref-manual/variables.rst

@@ -3839,7 +3839,7 @@ system and gives an overview of their function and contents.
    :term:`IMAGE_BOOT_FILES`
       A space-separated list of files installed into the boot partition
       when preparing an image using the Wic tool with the
-      ``bootimg-partition`` source plugin. By default,
+      ``bootimg_partition`` source plugin. By default,
       the files are
       installed under the same name as the source files. To change the
       installed name, separate it from the original name with a semi-colon
@@ -3917,7 +3917,7 @@ system and gives an overview of their function and contents.
    :term:`IMAGE_EFI_BOOT_FILES`
       A space-separated list of files installed into the boot partition
       when preparing an image using the Wic tool with the
-      ``bootimg-efi`` source plugin. By default,
+      ``bootimg_efi`` source plugin. By default,
       the files are
       installed under the same name as the source files. To change the
       installed name, separate it from the original name with a semi-colon