(starship): Quote pretty name.

Otherwise it does not work, if braces are in the string.

private_dot_config/starship.toml.tmpl

@@ -91,9 +91,9 @@ format = '[[ $symbol($version)](fg:#769ff0 bg:#212736)]($style)'
 
 [custom.os]
 {{ if eq .chezmoi.os "linux" }}
-command = 'echo {{ .chezmoi.osRelease.prettyName }}'
+command = 'echo "{{ .chezmoi.osRelease.prettyName }}"'
 {{ else if eq .chezmoi.os "windows" }}
-command = 'echo {{ .chezmoi.windowsVersion.productName }}'
+command = 'echo "{{ .chezmoi.windowsVersion.productName }}"'
 {{ end }}
 when = true
 format = "[$output]($style)"