verbs: wrap abstract too

So far there's only one multi-line abstract. But as pointed out in the
review, it's silly to handle footer but not the abstract.

help_abstract() is not reused because it only works with one-line
abstracts. (It always prints an empty line to separate paragraphs.)
So the formatting is done anew in print_wrapped(). I think this is OK,
since it's all very simple. After everything has been converted to
COMMAND() and its helpers, help_abstract() and the sister functions will
become unused and can be dropped then.

src/resolve/resolvectl.c

@@ -97,7 +97,7 @@ STATIC_DESTRUCTOR_REGISTER(arg_set_nta, strv_freep);
 
 COMMAND(
         "resolvectl\0",
-        "Send control commands to the network name resolution manager, or\n"
+        "Send control commands to the network name resolution manager, or "
         "resolve domain names, IPv4 and IPv6 addresses, DNS records, and services.",
         .man_pages = "resolvectl.1\0",
         .option_namespace = "resolvectl",