DOCS-15473 Update exit codes reference (#2070)

Author: nvillahermosa-mdb

source/reference/exit-codes.txt

@@ -14,6 +14,7 @@ MongoDB will return one of the following codes and statuses when
 exiting. Use this guide to interpret logs and when troubleshooting
 issues with :binary:`~bin.mongod` and :binary:`~bin.mongos` instances.
 
+.. _exit-codes:
 
 .. list-table::
    :header-rows: 1
@@ -25,47 +26,45 @@ issues with :binary:`~bin.mongod` and :binary:`~bin.mongos` instances.
    * - .. error:: 0
      - Returned by MongoDB applications upon successful exit.
 
-       .. symbol: EXIT_CLEAN
+
+   * - .. error:: 1
+     - Returned by :binary:`~bin.mongod` as a generic failure when no 
+       other error codes apply.
+
 
    * - .. error:: 2
      - The specified options are in error or are incompatible
        with other options.
 
-       .. symbol: EXIT_BADOPTIONS 2
 
    * - .. error:: 3
-     - Returned by :binary:`~bin.mongod` if there is a mismatch
-       between hostnames specified on the command line and in the
-       ``local.sources`` collection, in master/slave mode.
+     - Returned by :binary:`~bin.mongod` if there is a mismatch between 
+       hostnames specified on the command line and in the 
+       ``local.sources`` collection when running a replica set.
 
-       .. symbol: EXIT_REPLICATION_ERROR = 3
 
    * - .. error:: 4
      - The version of the database is different from the version
        supported by the :binary:`~bin.mongod` (or
        :binary:`~bin.mongod.exe`) instance.  The instance exits
        cleanly.
 
-       .. symbol: EXIT_NEED_UPGRADE = 4
 
    * - .. error:: 5
      - Returned by :binary:`~bin.mongos` if a problem is encountered
        during initialization.
 
-       .. symbol: EXIT_SHARDING_ERROR = 5
 
    * - .. error:: 12
      - Returned by the :binary:`~bin.mongod.exe` process on Windows
        when it receives a Control-C, Close, Break or Shutdown event.
 
-       .. symbol: EXIT_KILL = 12
 
    * - .. error:: 14
      - Returned by MongoDB applications which encounter an
        unrecoverable error, an uncaught exception or uncaught signal.
        The system exits without performing a clean shutdown.
 
-       .. symbol: EXIT_ABRUPT = 14
 
    * - .. error:: 20
      - *Message:* ``ERROR: wsastartup failed <reason>``
@@ -80,30 +79,50 @@ issues with :binary:`~bin.mongod` and :binary:`~bin.mongos` instances.
        installing, starting or removing the NT Service for the
        application.
 
-       .. symbol: EXIT_NTSERVICE_ERROR = 20
 
    * - .. error:: 48
-     - A newly started :binary:`~bin.mongod` or :binary:`~bin.mongos`
-       could not start listening for incoming connections, due to an
-       error.
+     - Returned by :binary:`~bin.mongod` or :binary:`~bin.mongos`
+       when an error prevents a newly started instance from listening 
+       for incoming connections.
+
+
+   * - .. error:: 50
+     - Returned by :binary:`~bin.mongod` during server initialization 
+       if it fails to fork the process.
+       
+
+   * - .. error:: 51
+     - Returned by :binary:`~bin.mongod` during server initialization 
+       if the daemon fails to send a ready signal. The process exits 
+       cleanly.
 
-       .. symbol: EXIT_NET_ERROR = 48
 
    * - .. error:: 61
      - Returned by the :ref:`storage-node-watchdog` if any of the 
        filesystems with monitored directories are unresponsive.
 
-       .. symbol: EXIT_WATCHDOG = 61
 
    * - .. error:: 62
-     - Returned by :binary:`~bin.mongod` if the datafiles in
+     - Returned by :binary:`~bin.mongod` when the datafiles in
        :option:`--dbpath <mongod --dbpath>` are incompatible with the
-       version of :binary:`~bin.mongod` currently running.
+       version of :binary:`~bin.mongod` currently running. 
+       
+       To resolve data incompatibility issues after upgrading, please 
+       refer to the :ref:`release notes <release-notes-6.0>` for your 
+       version of MongoDB and search for "Changes Affecting 
+       Compatibility."
+
+
+   * - .. error:: 87
+     - Returned by :binary:`~bin.mongod` or :binary:`~bin.mongos` when 
+       the process health check triggers a crash.
 
-       .. symbol: EXIT_NEED_DOWNGRADE = 62
 
    * - .. error:: 100
      - Returned by :binary:`~bin.mongod` when the process throws an
        uncaught exception.
 
-       .. symbol: EXIT_UNCAUGHT = 100
+
+   * - .. error:: 102
+     - Returned by :binary:`~bin.mongod` or :binary:`~bin.mongos` when 
+       the process fails to rotate audit logs on startup.