docs(schema): Apply suggestions from code review

Co-authored-by: Thales Macedo Garitezi <thalesmg@gmail.com>

apps/emqx/etc/emqx.conf

@@ -894,7 +894,7 @@ conn_congestion {
   ## Whether to alarm the congested connections.
   ##
   ## Sometimes the mqtt connection (usually an MQTT subscriber) may
-  ## get "congested", because there're too many packets to sent.
+  ## get "congested", because there're too many packets to be sent.
   ## The socket tries to buffer the packets until the buffer is
   ## full. If more packets come after that, the packets will be
   ## "pending" in a queue and we consider the connection is

apps/emqx/src/emqx_schema.erl

@@ -1740,7 +1740,7 @@ desc("zone") ->
     "}\n"
     "```\n\n"
     "The global config `a` is overridden by the configs `a` inside the zone `my_zone`.\n\n"
-    "If there is a listener uses the zone `my_zone`, the value of config `a` will be: "
+    "If there is a listener using the zone `my_zone`, the value of config `a` will be: "
     "`{b:2, c: 1}`.\n"
     "Note that although the default value of `a.c` is `0`, the global value is used,"
     " i.e. configs in the zone have no default values. To override `a.c` one must configure"
@@ -1771,7 +1771,7 @@ desc("overload_protection") ->
 desc("conn_congestion") ->
     "Settings for `conn_congestion` alarm.\n\n"
     "Sometimes the MQTT connection (usually an MQTT subscriber) may\n"
-    "get \"congested\", because there are too many packets to sent.\n"
+    "get \"congested\", because there are too many packets to be sent.\n"
     "The socket tries to buffer the packets until the buffer is\n"
     "full. If more packets arrive after that, the packets will be\n"
     "\"pending\" in the queue and we consider the connection\n"

apps/emqx_conf/src/emqx_conf_schema.erl

@@ -756,7 +756,7 @@ desc("rpc") ->
     "EMQX uses a library called <code>gen_rpc</code> for "
     "inter-broker communication.<br/>Most of the time the default config "
     "should work, but in case you need to do performance "
-    "fine-turning or experiment a bit, this is where to look.";
+    "fine-tuning or experiment a bit, this is where to look.";
 desc("log") ->
     "EMQX logging supports multiple sinks for the log events."
     " Each sink is represented by a _log handler_, which can be configured independently.";
@@ -769,7 +769,7 @@ desc("log_rotation") ->
     " or in `/var/log/emqx` (for binary installation).<br/>"
     "This section of the configuration controls the number of files kept for each log handler.";
 desc("log_overload_kill") ->
-    "Log overload kill feature an overload protection that activates when"
+    "Log overload kill features an overload protection that activates when"
     " the log handlers use too much memory or have too many buffered log messages.<br/>"
     "When the overload is detected, the log handler is terminated and restarted after a"
     " cooldown period.";