refactor: Adjust again to latest 'simple' commit

Now with even less code!

tests/fixtures/recursive-inclusion/baz.qux

@@ -2,7 +2,7 @@ I'd like you to know that
 really just about anything can go up here.
 START right here, because everything else on this line is ignored:
 | file
- in{! xyzzy start: '(.*)' !}ion
+ in{! xyzzy extract: {start: '(.*)'} !}ion
 STOP that distraction!
 Now we can get back to our originally
 scheduled qux.

tests/fixtures/recursive-inclusion/foo.bar

@@ -12,9 +12,10 @@ Point: This should be ignored by semiliterate extraction.
 ---
 And other features, such as extraction resumption.
 
-Not to mention{! baz.qux start: START
-terminate: STOP
-replace: ['^\|(.*)$'] !}syntax and `{! escaped syntax !}`.
+Not to mention{! baz.qux extract:
+  start: START
+  replace: ['^\|(.*)$']
+terminate: STOP !}syntax and `{! escaped syntax !}`.
 ---
 
 Unfortunate: the bar language has no real structure

tests/fixtures/recursive-inclusion/mkdocs.yml

@@ -7,8 +7,7 @@ plugins:
     copy_standard_markdown: true
     semiliterate:
     - pattern: '(\.bar)$'
-      start: '---'
-      stop: '---'
+      extract: {start: '---', stop: '---'}
       terminate: '!!!'
 nav:
 - About: README.md