DOCS-8981: Document maxLogSizeKB parameter

Also fix two minor typos.

Author: kallimachos

source/reference/command/setParameter.txt

@@ -34,6 +34,7 @@ setParameter
    - :parameter:`logComponentVerbosity`
    - :parameter:`logLevel`
    - :parameter:`logUserIds`
+   - :parameter:`maxLogSizeKB`
    - :parameter:`quiet`
    - :parameter:`traceExceptions`
 

source/reference/parameters.txt

@@ -736,6 +736,26 @@ Logging Parameters
 
    Disabled by default.
 
+.. parameter:: maxLogSizeKB
+
+   .. versionadded:: 3.4
+
+   |both|
+
+   *Type*: integer
+
+   *Default*: 10
+
+   Specifies the maximum size, in kilobytes, for a log line. Lines exceeding
+   this limit print only the beginning and end of the line, excising the middle
+   portion.
+
+   For example, the following sets the maximum size to ``20`` kilobytes:
+
+   .. code-block:: sh
+
+      mongod --setParameter maxLogSizeKB=20
+
 .. parameter:: quiet
 
    |both|
@@ -846,7 +866,7 @@ The following parameters support :term:`diagnostic data capture (FTDC)
 
    |mongos-only|
 
-   Specify the the directory for the diagnostic directory for
+   Specify the directory for the diagnostic directory for
    :program:`mongos`. If the directory does not exist,
    :program:`mongos` creates the directory.
 
@@ -882,7 +902,7 @@ The following parameters support :term:`diagnostic data capture (FTDC)
    *Default*: 200
 
    Specifies the maximum size, in megabytes, of the ``diagnostic.data``
-   directory . If directory size exceeds this number, the oldest
+   directory. If directory size exceeds this number, the oldest
    :ref:`diagnostic files in the directory
    <3.2-diagnostic-data-capture>` are automatically deleted based on
    the timestamp in the file name.