add "versions" to docs subtitle (asdf-vm#462)

jthegedus · web-flow · commit abea57501df1 · 2019-02-11T17:39:15.000+11:00
as with asdf-vm#460
diff --git a/docs/_coverpage.md b/docs/_coverpage.md
@@ -2,7 +2,7 @@
 
 # asdf-vm
 
-> Manage multiple runtimes with a single CLI tool
+> Manage multiple runtime versions with a single CLI tool
 
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