=doc #18657 Doc host and path directives

* also including docs of RequestVals.matchAndExtractHost
  and RequestVals.matchAndExtractHost
* and add Host.create factory methods
* add missing HttpRequest PATCH and OPTIONS
* change to val in matchAndExtractHost for
  fail fast exception

akka-docs-dev/rst/java/http/routing-dsl/directives/method-directives/index.rst

@@ -0,0 +1,18 @@
+.. _MethodDirectives:
+
+MethodDirectives
+================
+
+.. toctree::
+   :maxdepth: 1
+
+   delete
+   extractMethod
+   get
+   head
+   method
+   options
+   overrideMethodWithParameter
+   patch
+   post
+   put