use minimal afl input

afl exits early when initial input crashes, which it often does after
large changes

tests/afl/in/all.dj

@@ -1,35 +1 @@
-{.class}
+a
-{#id}
-{attr=value}
-# heading
-
-## sub heading
-
-para
-
-::: div-class
-
-- list item
-
-    - indented list item
-
-```lang
-code block
-```
-
-:::
-
-> blockquote
-> > inner
-> > inner
-> outer
-
-[tag]: url
-[^footnote]: description
-
-inline `verbatim` _emphasis_, *strong*, ^sup^, ~sub~, {-del-}, {+ins+} \
-[link][], [text][tag], [text](url), ![alt text](src), <https://example.com>,
-<mail@example.com>, {=mark=}, 'single', "double", $`inline`, $$`display`
-{%comment%}, [span of text]{with=some .attributes}, $`<em>raw html</em>`{=html}
-
-- * - * - * -