man: move ctr.1, containerd-config to section 8, and fix generation

I missed this in my previous change: the ctr man page is also
in Section 8, because it's considered an administrative tool,
and containerd-config is related to containerd so updating these
as well.

This commit also fixes naming of the generated files, which was
hard-coded to .1.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

docs/man/containerd-config.8.md

@@ -1,4 +1,4 @@
-# containerd-config 1 01/30/2018
+# containerd-config 8 01/30/2018
 
 ## NAME
 
@@ -38,4 +38,4 @@ Phil Estes <estesp@gmail.com>
 
 ## SEE ALSO
 
-ctr(1), containerd(8), containerd-config.toml(5)
+ctr(8), containerd(8), containerd-config.toml(5)

docs/man/containerd-config.toml.5.md

@@ -142,4 +142,4 @@ Phil Estes <estesp@gmail.com>
 
 ## SEE ALSO
 
-ctr(1), containerd-config(1), containerd(8)
+ctr(8), containerd-config(8), containerd(8)