Add hello world Go app

Co-authored-by: bool <bolaji.olajide@sourcegraph.com>

Author: asdf-bolaji-testing[bot]

go.mod

@@ -0,0 +1,3 @@
+module github.com/sourcegraph-testing/markdowns
+
+go 1.22

main.go

@@ -0,0 +1,7 @@
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("Hello, world!")
+}