Fix correct/incorrect example in "Templates - Names of Defined Templates"

[ILyaCyclone]

On Templates page https://helm.sh/docs/chart_best_practices/templates/#names-of-defined-templates in "Names of Defined Templates" section there is following text:

helm-www/content/en/docs/chart_best_practices/templates.md

Lines 29 to 45 in 7edf25d

	For that reason, _all defined template names should be namespaced._
	Correct:
	```yaml
	{{- define "nginx.fullname" }}
	{{/* ... */}}
	{{ end -}}
	```
	Incorrect:
	```yaml
	{{- define "fullname" -}}
	{{/* ... */}}
	{{ end -}}
	```

This section describes necessity of using namespaces in variables names, so the key difference is "nginx.fullname" vs "fullname".
But current and incorrect examples are also different in a dash symbol, added at the end of define in incorrect one: "{{- define "fullname" -}}".

I believe the only difference should be in naming: "nginx.fullname" vs "fullname".