config: Consistent Markdown/Go wording for 'hostname'

I've changed the old "as it is accessible to ..." to the more compact
"as seen by ..." language from the old Markdown version, although I
don't think it's strictly necessary.  The original "accessbile to"
language is from 77d44b10 (Update runtime.md, 2015-06-16), which
actually looked fairly similar to the language I'm using here.  That
commit's "hostname for the container" lanuage went away in 7ac41c69
(config.md: reformat into a standard style, 2015-06-30), although that
commit made too many changes to motivate them all at that level.

I've left that language out of the Go comment, because truncating for
compact Go comments is fine (the Markdown entry is canonical, and the
Go comment is just to provide some minimal context).

Signed-off-by: W. Trevor King <wking@tremily.us>

config.md

@@ -191,7 +191,7 @@ _Note: For Solaris, uid and gid specify the uid and gid of the process inside th
 
 ## Hostname
 
-* **`hostname`** (string, optional) as it is accessible to processes running inside.
+* **`hostname`** (string, optional) configures the container's hostname as seen by processes running inside the container.
   On Linux, you can only set this if your bundle creates a new [UTS namespace][uts-namespace].
 
 ### Example

specs-go/config.go

@@ -12,7 +12,7 @@ type Spec struct {
 	Process Process `json:"process"`
 	// Root configures the container's root filesystem.
 	Root Root `json:"root"`
-	// Hostname is the container's host name.
+	// Hostname configures the container's hostname.
 	Hostname string `json:"hostname,omitempty"`
 	// Mounts profile configuration for adding mounts to the container's filesystem.
 	Mounts []Mount `json:"mounts,omitempty"`