Fix template example name

The naming conventions for test functions are a bit special and
different to the normal naming conventions in Go. They are documented
here [1].

This had the effect that godoc and pkg.go.dev did not display this
example.

Testing with `godoc` locally helped to debug this. Calling `go install
golang.org/x/tools/cmd/godoc@latest` helped with the installation.

[1]: https://go.dev/blog/examples

1 files changed, 1 insertions, 1 deletions

diff --git a/optional/template_test.go b/optional/template_test.go
index ab4ce76..83b5821 100644
--- a/optional/template_test.go
+++ b/optional/template_test.go
@@ -8,7 +8,7 @@ import (
 	"xengineering.eu/optional-go/optional"
 )
 
-func ExampleTemplate() {
+func Example_template() {
 	data := struct {
 		Flag optional.Optional[bool]
 	}{