build: rtd: don't specify format and install asciidoc dependency

The nvme-cli build fails due an invalid formats and the libnvme build
due to missing a build dependency. Fix those bugs.

Signed-off-by: Daniel Wagner <[email protected]>

Author: igaw

.readthedocs.yaml

@@ -19,4 +19,4 @@ build:
         - cp .build-ci/*.html $READTHEDOCS_OUTPUT/html/
         - mv $READTHEDOCS_OUTPUT/html/nvme.html $READTHEDOCS_OUTPUT/html/index.html
 
-formats: [html]
+formats: []

libnvme/.readthedocs.yaml

@@ -11,6 +11,7 @@ build:
     - docbook-xsl
     - xsltproc
     - pandoc
+    - asciidoc
   jobs:
     pre_build:
       - scripts/build.sh rst_docs