Add short flags to help, add --help flag

This prints the short variants (like `-c` for `--config`)
in the help.

Also fixes bug where only `-h` flag works, not `--help`.

internal/config/arguments.go

@@ -22,7 +22,7 @@ func argParse() {
 			continue
 		}
 		switch arg {
-		case "-h":
+		case "-h", "--help":
 			CLI.printUsage()
 		case "-c", "--config":
 			if len(os.Args) < i+2 {

internal/config/help.go

@@ -18,12 +18,12 @@ var CLI = help{
 	title:   Title,
 	version: Version,
 	usage: map[int][]string{
-		0: {0: "--config", 1: "<file>", 2: "Specify config file"},
+		0: {0: "-c, --config", 1: "<file>", 2: "Specify config file"},
 		1: {0: "--nocolor", 1: "disable color and banner"},
 		2: {0: "--banner", 1: "show banner + version and exit"},
 		3: {0: "--genconfig", 1: "write default config to " + Title + ".toml then exit"},
-		4: {0: "--book", "<file>", "Specify a custom file used for text generation"},
-		5: {0: "--help", 1: "show this help and exit"},
+		4: {0: "-b, --book", 1: "<file>", 2: "Specify a custom file used for text generation"},
+		5: {0: "-h, --help", 1: "show this help and exit"},
 	},
 	out: os.Stdout,
 }