Remove existence check from templates before range

[javorszky]

Closes #8095

Per testing and documentation the if guard to check if a slice is not empty or not nil is not necessary.

Documentation:

{{range pipeline}} T1 {{end}}
The value of the pipeline must be an array, slice, map, iter.Seq,
iter.Seq2, integer or channel.
If the value of the pipeline has length zero, nothing is output;
otherwise, dot is set to the successive elements of the array,
slice, or map and T1 is executed. If the value is a map and the
keys are of basic type with a defined order, the elements will be
visited in sorted key order.

https://pkg.go.dev/text/template#hdr-Actions

Code testing:

<p>begin</p> {{ range $value := .Elements }} <p>{{ $value }}</p> {{ end }} <p>end</p> 

struct that gets populated with data:

type Example struct { Elements []string } 

executed with the following data:

// slice is not empty e := Example{ Elements: []string{"one", "two", "three"} } // slice is empty, but initialised eEmpty := Example { Elements: []string{} } // slice is nil eNil := Example { Elements: nil } 

The output for these three in order:

<p>begin</p> <p>Element 1</p> <p>Element 2</p> <p>Element 3</p> <p>end</p> <p>begin</p> <p>end</p> <p>begin</p> <p>end</p> 

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork