Rename to "What's Crossplane"

Vale says it's better.

Signed-off-by: Nic Cope <nicc@rk0n.org>

Author: negz

…2.0-preview/what-is-crossplane/_index.md …/v2.0-preview/whats-crossplane/_index.mdcontent/v2.0-preview/what-is-crossplane/_index.md renamed to content/v2.0-preview/whats-crossplane/_index.md content/v2.0-preview/what-is-crossplane/_index.md renamed to content/v2.0-preview/whats-crossplane/_index.md

@@ -1,5 +1,5 @@
 ---
-title: What is Crossplane?
+title: What's Crossplane?
 weight: 3
 description: Learn what Crossplane is and why you'd use it.
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