Fix spelling

doc/rtd/reference/yaml_examples/apt.rst

@@ -82,17 +82,17 @@ There is no harm in specifying a suite to be disabled that is not found in the
 ---------------------------------
 
 Default: none - instead it is auto select based on cloud metadata so if
-neither "uri" nor "search", nor "search_dns" is set (the default) then use
+none of ``uri``, ``search``, or ``search_dns`` are set (the default) then use
 the mirror provided by the DataSource found. In EC2, that means using
 ``<region>.ec2.archive.ubuntu.com``.
 
 ``security`` is optional, if not defined it is set to the same value as
 primary.
 
 Define a custom (e.g. localized) mirror that will be used in ``sources.list``
-and any custom sources entries for deb / deb-src lines.
+and any custom sources entries for ``deb`` / ``deb-src`` lines.
 
-One can set primary and security mirror to different uri's. The child
+One can set primary and security mirror to different URIs. The child
 elements to the keys primary and secondary are equivalent.
 
 * ``arches`` is list of architectures the config applies to. The special
@@ -105,8 +105,8 @@ elements to the keys primary and secondary are equivalent.
   first with a working DNS resolution (or if it is an IP) will be picked.
   That way one can keep one configuration for multiple sub-environments that
   select the working one.
-* ``search_dns`` If no mirror is provided by uri or search but 'search_dns'
-  is true, then search for dns names ``'<distro>-mirror'`` in each of:
+* ``search_dns`` If no mirror is provided by URI or search but 'search_dns'
+  is true, then search for DNS names ``'<distro>-mirror'`` in each of:
 
   - FQDN of this host per cloud metadata
   - ``localdomain``