command-line-interface: Add cross-references to bundle/runtime/glossary

Now that this document is in runtime-spec we can be more liberal with
the linking.

Signed-off-by: W. Trevor King <[email protected]>

Author: wking

command-line-interface.md

@@ -1,6 +1,6 @@
 # Operations
 
-A conformant runtime MUST provide an executable (called `funC` in the following examples).
+A conformant [runtime][] MUST provide an executable (called `funC` in the following examples).
 That executable MUST support commands with the following template:
 
 ```sh
@@ -47,12 +47,12 @@ $ echo $?
 
 ### start
 
-Start a container from a bundle directory.
+[Start][start] a container from a [bundle directory][bundle].
 
 * *Options*
   * *`--id <ID>`* Set the container ID when creating a container.
     If not set, the runtime is free to pick any ID that is not already in use.
-  * *`--bundle <PATH>`* Override the path to the bundle directory (defaults to the current working directory).
+  * *`--bundle <PATH>`* Override the path to the [bundle directory][bundle] (defaults to the current working directory).
 * *Standard streams:* The runtime MUST attach its standard streams directly to the application process without inspection.
 * *Environment variables*
   * *`LISTEN_FDS`:* The number of file descriptors passed.
@@ -72,13 +72,13 @@ $ echo $?
 
 ### state
 
-Request the container state.
+[Request][state-request] the container [state][state].
 
 * *Arguments*
   * *`<ID>`* The container whose state is being requested.
 * *Standard streams:*
   * *stdin:* The runtime MUST NOT attempt to read from its stdin.
-  * *stdout:* The runtime MUST print the state JSON to its stdout.
+  * *stdout:* The runtime MUST print the [state JSON][state] to its stdout.
   * *stderr:* The runtime MAY print diagnostic messages to stderr, and the format for those lines is not specified in this document.
 * *Exit code:* Zero if the state was successfully written to stdout and non-zero on errors.
 
@@ -102,8 +102,13 @@ $ echo $?
 0
 ```
 
+[bundle]: bundle.md
 [posix-encoding]: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap06.html#tag_06_02
 [posix-lang]: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_02
 [posix-locale-encoding]: http://www.unicode.org/reports/tr35/#Bundle_vs_Item_Lookup
+[runtime]: glossary.md#runtime
+[start]: runtime.md#start
+[state]: runtime.md#state
+[state-request]: runtime.md#query-state
 [systemd-listen-fds]: http://www.freedesktop.org/software/systemd/man/sd_listen_fds.html
 [UTF-8]: http://www.unicode.org/versions/Unicode8.0.0/ch03.pdf