fix docs for merging and throttling

docs/reference/index-modules/merge.asciidoc

@@ -201,8 +201,9 @@ The scheduler supports the following settings:
 
 `index.merge.scheduler.max_thread_count`::
 
-The maximum number of threads to perform the merge operation. Defaults to
-`Math.max(1, Math.min(3, Runtime.getRuntime().availableProcessors() / 2))`.
+The maximum number of concurrent merge threads that may run at once. Defaults
+to `1` which works best with spinning-magnets disks.  If you are using
+a good solid-state disk (SSD) instead then try setting this to `3`.
 
 [float]
 ==== SerialMergeScheduler

docs/reference/modules/indices.asciidoc

@@ -69,7 +69,7 @@ The following settings can be set to control the store throttling:
 
 [horizontal]
 `indices.store.throttle.type`::
-    could be `merge` (default), `not` or `all`. See <<index-modules-store>>.
+    could be `merge` (default), `none` or `all`. See <<index-modules-store>>.
 
 `indices.store.throttle.max_bytes_per_sec`::
     defaults to `50mb`.