migrate docs to mdx

website/docs/language/functions/contains.mdx

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+---
+page_title: contains - Functions - Configuration Language
+description: The contains function determines whether a list or set contains a given value.
+sidebar_title: contains
+---
+
+# `contains` Function
+
+`contains` determines whether a given list or set contains a given single value
+as one of its elements.
+
+```hcl
+contains(list, value)
+```
+
+## Examples
+
+```
+> contains(["a", "b", "c"], "a")
+true
+> contains(["a", "b", "c"], "d")
+false
+```