Added template functions for multi-line Description formatting.

template.go

@@ -13,7 +13,7 @@ VERSION:
    {{.Version}}{{end}}{{end}}{{if .Description}}
 
 DESCRIPTION:
-   {{.Description}}{{end}}{{if len .Authors}}
+   {{.Description | nindent 3 | trim}}{{end}}{{if len .Authors}}
 
 AUTHOR{{with $length := len .Authors}}{{if ne 1 $length}}S{{end}}{{end}}:
    {{range $index, $author := .Authors}}{{if $index}}
@@ -45,7 +45,7 @@ CATEGORY:
    {{.Category}}{{end}}{{if .Description}}
 
 DESCRIPTION:
-   {{.Description}}{{end}}{{if .VisibleFlags}}
+   {{.Description | nindent 3 | trim}}{{end}}{{if .VisibleFlags}}
 
 OPTIONS:
    {{range .VisibleFlags}}{{.}}
@@ -62,7 +62,7 @@ USAGE:
    {{if .UsageText}}{{.UsageText}}{{else}}{{.HelpName}} command{{if .VisibleFlags}} [command options]{{end}} {{if .ArgsUsage}}{{.ArgsUsage}}{{else}}[arguments...]{{end}}{{end}}{{if .Description}}
 
 DESCRIPTION:
-   {{.Description}}{{end}}
+   {{.Description | nindent 3 | trim}}{{end}}
 
 COMMANDS:{{range .VisibleCategories}}{{if .Name}}
    {{.Name}}:{{range .VisibleCommands}}