Changing some grammar in docs (#24164)

Author: ianomad

docs/reference/modules/discovery/zen.asciidoc

@@ -75,7 +75,7 @@ The `discovery.zen.minimum_master_nodes` sets the minimum
 number of master eligible nodes that need to join a newly elected master in order for an election to
 complete and for the elected node to accept its mastership. The same setting controls the minimum number of
 active master eligible nodes that should be a part of any active cluster. If this requirement is not met the
-active master node will step down and a new master election will be begin.
+active master node will step down and a new master election will begin.
 
 This setting must be set to a quorum of your master eligible nodes. It is recommended to avoid
 having only two master eligible nodes, since a quorum of two is two. Therefore, a loss
@@ -140,7 +140,7 @@ The `discovery.zen.no_master_block` setting has two valid options:
 `all`:: All operations on the node--i.e. both read & writes--will be rejected. This also applies for api cluster state
 read or write operations, like the get index settings, put mapping and cluster state api.
 `write`:: (default) Write operations will be rejected. Read operations will succeed, based on the last known cluster configuration.
-This may result in partial reads of stale data as this node may be isolated from the rest of the cluster. 
+This may result in partial reads of stale data as this node may be isolated from the rest of the cluster.
 
 The `discovery.zen.no_master_block` setting doesn't apply to nodes-based apis (for example cluster stats, node info and
 node stats apis).  Requests to these apis will not be blocked and can run on any available node.