Docs: Add ccr to the cat thread pool doc test

Since elastic#31251, we use the default distribution to test docs. With this
distribution, the cat thread-pool response will include the ccr
thread-pool. This commit adjusts /_cat/thread_pool doc to include ccr.

Relates elastic#31251

Author: dnhatn

docs/reference/cat/thread_pool.asciidoc

@@ -15,6 +15,7 @@ Which looks like:
 [source,txt]
 --------------------------------------------------
 node-0 analyze             0 0 0
+...
 node-0 fetch_shard_started 0 0 0
 node-0 fetch_shard_store   0 0 0
 node-0 flush               0 0 0
@@ -45,6 +46,7 @@ The second column is the thread pool name
 --------------------------------------------------
 name
 analyze
+ccr (default distro only)
 fetch_shard_started
 fetch_shard_store
 flush
@@ -81,6 +83,7 @@ active queue rejected
      0     0        0
      0     0        0
      0     0        0
+     0     0        0
      1     0        0
      0     0        0
      0     0        0