Cleanup config header for libcmd

- Since it's now private, give it a rename. Note that I want to switch the
  word order on the public ones too.

- Since it is only needed by two files, just include there rather than
  the nasty blanket-forced thing.

(cherry picked from commit 326548bae5)

src/libcmd/markdown.cc

@@ -4,6 +4,8 @@
 #include "finally.hh"
 #include "terminal.hh"
 
+#include "cmd-config-private.hh"
+
 #if HAVE_LOWDOWN
 #  include <sys/queue.h>
 #  include <lowdown.h>

src/libcmd/meson.build

@@ -55,7 +55,7 @@ endif
 
 config_h = configure_file(
   configuration : configdata,
-  output : 'config-cmd.hh',
+  output : 'cmd-config-private.hh',
 )
 
 add_project_arguments(
@@ -64,7 +64,6 @@ add_project_arguments(
   '-include', 'config-util.hh',
   '-include', 'config-store.hh',
   '-include', 'config-expr.hh',
-  '-include', 'config-cmd.hh',
   language : 'cpp',
 )
 

src/libcmd/repl-interacter.cc

@@ -1,3 +1,5 @@
+#include "cmd-config-private.hh"
+
 #include <cstdio>
 
 #ifdef USE_READLINE