Add package level doc comment to llvm

llvm/doc.go

@@ -0,0 +1,8 @@
+// Package llvm provides a way to build and write out LLVM modules.
+// 
+// This package was created for the express purpose of generating LLVM IR. A
+// good portion of this code was taken from https://github.com/llir/llvm. As
+// such, it does not contain features such as sanity checking and IR parsing.
+// The main reason this package was created was to add support for opaque
+// pointers and drop support for the legacy typed ones.
+package llvm