update docs to reflect parameter method change

docs/api/crash-reporter.md

@@ -120,8 +120,6 @@ called before `start` is called.
 
 * `key` String - Parameter key, must be less than 64 characters long.
 * `value` String - Parameter value, must be less than 64 characters long.
-  Specifying `null` or `undefined` will remove the key from the extra
-  parameters.
 
 Set an extra parameter to be sent with the crash report. The values
 specified here will be sent in addition to any values set via the `extra` option
@@ -129,6 +127,16 @@ when `start` was called. This API is only available on macOS, if you need to
 add/update extra parameters on Linux and Windows after your first call to
 `start` you can call `start` again with the updated `extra` options.
 
+### `crashReporter.removeExtraParameter(key)` _macOS_
+
+* `key` String - Parameter key, must be less than 64 characters long.
+
+Remove a extra parameter from the current set of parameters so that it will not be sent with the crash report.
+
+### `crashReporter.getParameters()`
+
+See all of the current parameters being passed to the crash reporter.
+
 ## Crash Report Payload
 
 The crash reporter will send the following data to the `submitURL` as