[#3084] addressed review comments

- fixing mostly typos

doc/sphinx/arm/hooks-ping-check.rst

@@ -5,9 +5,9 @@
 =====================================
 
 This hook library adds the ability to perform a "ping check" of a candidate
-IPv4 address prior to offering it to a DHCP client.  This feature is similar
+IPv4 address prior to offering it to a DHCP client. This feature is similar
 to a behavior available in ISC DHCP and one suggested in `RFC
-2131 <https://tools.ietf.org/html/rfc2131>`__ , see section 3.2, item 2.
+2131 <https://tools.ietf.org/html/rfc2131>`__ , see section 3.1, item 2.
 
 .. note::
 
@@ -51,7 +51,7 @@ offering a lease to client if all of the following conditions are true
 
     a. This is the first offer of this lease to this client. This check
     can only be done if `offer-lifetime` is greater than zero (i.e. temporary
-    allocation on DHCPDISCOVER is enabled).  If `offer-lifetime` is zero
+    allocation on DHCPDISCOVER is enabled). If `offer-lifetime` is zero
     ping checks are done for every DHCPOFFER as the server has no way to
     know it has made prior offers.
 
@@ -102,9 +102,9 @@ return to step 1.
 
 .. note::
 
-    Socket buffer full errors indicate that the OS rate limits on ICMP are being
-    been exceeded.  The server will not retry them as this would likely only
-    exacerbate the situation.  If this occurs continuously then the client load
+    Socket buffer full of errors indicates that the OS rate limits on ICMP are
+    being exceeded. The server will not retry them as this would likely only
+    exacerbate the situation. If this occurs continuously then the client load
     on the server may be too high to accommodate ping checking. Ping checking is
     not recommended for systems with high throughput demands.
 
@@ -112,19 +112,19 @@ Configuration
 ~~~~~~~~~~~~~
 
 The ping-check hook library currently supports the following configuration parameters
-that may be set the global and subnet levels.  Subnet values override global values.
+that may be set at the global and subnet levels. Subnet values override global values.
 
 - `enable-ping-check` - Enables or disables ping checking at a given scope.
 
 - `min-ping-requests` - The minimum number of ECHO REQUESTs sent without receiving a reply needed to declare an address available. The default is 1, it must be greater than zero.
 
-- `reply-timeout` The maximum amount of time to wait for a reply to a single ECHO REQUEST. Specified in milliseconds, it must be greater than zero, it defaults to 100.
+- `reply-timeout` - The maximum amount of time to wait for a reply to a single ECHO REQUEST. Specified in milliseconds, it must be greater than zero, it defaults to 100.
 
-- `ping-cltt-secs` The number of seconds that must elapse after the lease's CLTT before a ping check will be conducted when the client is the lease's previous owner. The default value is sixty seconds.
+- `ping-cltt-secs` - The number of seconds that must elapse after the lease's CLTT before a ping check will be conducted when the client is the lease's previous owner. The default value is sixty seconds.
 
-The following parameter is only supported the global level:
+The following parameter is only supported at the global level:
 
-- `ping-channel-threads` In multi-threaded mode, this is the number of threads in the channel's thread pool.  The default is 0 which instructs the code to use the same number of threads as Kea core.
+- `ping-channel-threads` - In multi-threaded mode, this is the number of threads in the channel's thread pool. The default is 0 which instructs the library to use the same number of threads as Kea core.
 
 The following configuration excerpt illustrates global level configuration:
 
@@ -174,6 +174,6 @@ The following excerpt demonstrates subnet level configuration:
 
 .. note::
 
-    Ping checking is not yet fully integrated with High Availability (HA).  When ping checking
+    Ping checking is not yet fully integrated with High Availability (HA). When ping checking
     concludes that an address is not available and a declined lease is created, no corresponding
     lease update is sent to HA peer(s).

src/bin/dhcp4/dhcp4_messages.cc

@@ -344,7 +344,7 @@ const char* values[] = {
     "DHCP4_RESPONSE_HOSTNAME_DATA", "%1: including Hostname option in the server's response: %2",
     "DHCP4_RESPONSE_HOSTNAME_GENERATE", "%1: server has generated hostname %2 for the client",
     "DHCP4_SERVER_FAILED", "server failed: %1",
-    "DHCP4_SERVER_INITIATED_DECLINE", "Lease for addr %1 has been found to be already be in use. The lease will be unavailable for %2 seconds.",
+    "DHCP4_SERVER_INITIATED_DECLINE", "Lease for addr %1 has been found to be already in use. The lease will be unavailable for %2 seconds.",
     "DHCP4_SERVER_INITIATED_DECLINE_FAILED", "%1: error on server-initiated decline lease for address %2: %3",
     "DHCP4_SHUTDOWN", "server shutdown",
     "DHCP4_SHUTDOWN_REQUEST", "shutdown of server requested",

src/bin/dhcp4/dhcp4_messages.mes

@@ -1062,10 +1062,10 @@ This error message indicates that the software failed to decline a
 lease from the lease database due to an error during a database
 operation. The first argument includes the client and the transaction
 identification information. The second argument holds the IPv4 address
-which decline was attempted. The last one contains the reason for
+for which the decline was attempted. The last one contains the reason of
 failure.
 
-% DHCP4_SERVER_INITIATED_DECLINE Lease for addr %1 has been found to be already be in use. The lease will be unavailable for %2 seconds.
+% DHCP4_SERVER_INITIATED_DECLINE Lease for addr %1 has been found to be already in use. The lease will be unavailable for %2 seconds.
 This informational message is printed when the server has detected via
 ICMP ECHO (i.e. ping check) or other means that a lease which should be
 free to offer is actually in use. This message may indicate a misconfiguration