guest-agent: improve help for --allow-rpcs and --block-rpcs

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1757

Updates to qga help output and documentation for --allow-rpcs and --blocks-rpcs

Signed-off-by: "Angel M. Villegas" <anvilleg@cisco.com>
Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com>
Signed-off-by: Konstantin Kostiuk <kkostiuk@redhat.com>

docs/interop/qemu-ga.rst

@@ -81,13 +81,13 @@ Options
 
 .. option:: -b, --block-rpcs=LIST
 
-  Comma-separated list of RPCs to disable (no spaces, use ``help`` to
-  list available RPCs).
+  Comma-separated list of RPCs to disable (no spaces, use ``--block-rpcs=help``
+  to list available RPCs).
 
 .. option:: -a, --allow-rpcs=LIST
 
-  Comma-separated list of RPCs to enable (no spaces, use ``help`` to
-  list available RPCs).
+  Comma-separated list of RPCs to enable (no spaces, use ``--allow-rpcs=help``
+  to list available RPCs).
 
 .. option:: -D, --dump-conf
 

qga/main.c

@@ -261,9 +261,9 @@ QEMU_COPYRIGHT "\n"
 "  -s, --service     service commands: install, uninstall, vss-install, vss-uninstall\n"
 #endif
 "  -b, --block-rpcs  comma-separated list of RPCs to disable (no spaces,\n"
-"                    use \"help\" to list available RPCs)\n"
+"                    use \"--block-rpcs=help\" to list available RPCs)\n"
 "  -a, --allow-rpcs  comma-separated list of RPCs to enable (no spaces,\n"
-"                    use \"help\" to list available RPCs)\n"
+"                    use \"--allow-rpcs=help\" to list available RPCs)\n"
 "  -D, --dump-conf   dump a qemu-ga config file based on current config\n"
 "                    options / command-line parameters to stdout\n"
 "  -r, --retry-path  attempt re-opening path if it's unavailable or closed\n"