Polish Clarify @WithSecurityContext thread scope

Author: jzheaux

docs/modules/ROOT/pages/servlet/test/method.adoc

@@ -187,7 +187,7 @@ You can change this to happen during the `TestExecutionListener.beforeTestExecut
 [NOTE]
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 `@WithMockUser`, `@WithUserDetails`, and `@WithSecurityContext` populate the xref:servlet/authentication/architecture.adoc#servlet-authentication-securitycontextholder[`SecurityContextHolder`] for the test thread.
-This works for method-security tests and for xref:servlet/test/mockmvc/index.adoc[`MockMvc`] (when using `testSecurityContext()`), but does not automatically apply to full HTTP requests made through external clients (for example, REST-assured against a running server), because those requests are handled on a different thread.
+This cannot apply to full HTTP requests a test makes to a running server since those requests are handled by a different thread.
 For end-to-end HTTP tests, xref:servlet/authentication/index.adoc[authenticate] the request itself (for example, with HTTP Basic or a bearer token).
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