Spelling.

Signed-off-by: Phil Genera <[email protected]>

docs/root/operations/cli.rst

@@ -291,7 +291,7 @@ following are the command line options that Envoy supports.
 
   *(optional)* This flag disables validation of protobuf configuration for unknown fields in dynamic
    configuration. Unlike setting --reject-unknown-dynamic-fields to false, it does not log warnings or
-   count occurences of unknown fields, in the interest of configuration processing speed. If
+   count occurrences of unknown fields, in the interest of configuration processing speed. If
    --reject-unknown-dynamic-fields is set to true, this flag has no effect.
 
 .. option:: --disable-extensions <extension list>