Fix typo in the doc in 5.7 Multiple HttpSecurity

docs/manual/src/docs/asciidoc/index.adoc

@@ -944,7 +944,7 @@ public BCryptPasswordEncoder passwordEncoder() {
 
 === Multiple HttpSecurity
 
-We can configure multiple HttpSecurity instances just as we can have multiple `<http>` blocks. The key is to extend the `WebSecurityConfigurationAdapter` multiple times. For example, the following is an example of having a different configuration for URL's that start with `/api/`.
+We can configure multiple HttpSecurity instances just as we can have multiple `<http>` blocks. The key is to extend the `WebSecurityConfigurerAdapter` multiple times. For example, the following is an example of having a different configuration for URL's that start with `/api/`.
 
 [source,java]
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