vale: add exclamation rule

Signed-off-by: David Karlsson <35727626+dvdksn@users.noreply.github.com>

.github/vale/Docker/Exclamation.yml

@@ -0,0 +1,11 @@
+extends: existence
+message: "Don't use exclamation points in text."
+nonword: true
+level: error
+action:
+  name: edit
+  params:
+    - trim_right
+    - "!"
+tokens:
+  - '\w+!(?:\s|$)'