Optionally add line numbers to output

[biasedbit]

Optionally adds line numbers to each input file in the output file. Useful for tooling that consumes code and generates documentation with links to highlight certain portions (example highlight).

Line number padding is based on total number of lines in the file (none for files with < 10 lines).

Usage:

sandworm generate -n
sandworm generate --line-numbers

Example output:

================================================================================
FILE: cmd/sandworm/main.go
================================================================================
 1: // Package main is the main package for the sandworm CLI.
 2: package main
 3: 
 4: import (
 5: 	"os"
 6: 
 7: 	"github.com/holonoms/sandworm/internal/cli"
 8: )
 9: 
10: func main() {
11: 	if err := cli.NewRootCmd().Execute(); err != nil {
12: 		os.Exit(1)
13: 	}
14: }
15: