content/static: remove link to go.mod when file does not exist
Fixes golang/go#44837
Trust: Jamal Carvalho
Run-TryBot: Jamal Carvalho
TryBot-Result: kokoro
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{{template "unit_meta_details_check" .Unit.HasGoMod}}
- Valid <a href="{{.Details.ModFileURL}}" target="_blank">go.mod</a> file
+ Valid {{if .Unit.HasGoMod}}<a href="{{.Details.ModFileURL}}" target="_blank">{{end}}go.mod{{if .Unit.HasGoMod}}</a>{{end}} file
{{template "unit_meta_details_toggletip" "The Go module system was introduced in Go 1.11 and is the official dependency management solution for Go."}}
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