feat: implement --all flag

Implement an `--all` flag that can be used to view cheatsheets on all
chaetpaths. (Resolves #548)

cmd/cheat/cmd_view.go

@@ -30,9 +30,37 @@ func cmdView(opts map[string]interface{}, conf config.Config) {
 		)
 	}
 
-	// consolidate the cheatsheets found on all paths into a single map of
-	// `title` => `sheet` (ie, allow more local cheatsheets to override less
-	// local cheatsheets)
+	// if --all was passed, display cheatsheets from all cheatpaths
+	if opts["--all"].(bool) {
+		// iterate over the cheatpaths
+		for _, cheatpath := range cheatsheets {
+
+			// if the cheatpath contains the specified cheatsheet, display it
+			if sheet, ok := cheatpath[cheatsheet]; ok {
+
+				// identify the matching cheatsheet
+				fmt.Println(fmt.Sprintf("%s %s",
+					display.Underline(sheet.Title),
+					display.Faint(fmt.Sprintf("(%s)", sheet.CheatPath)),
+				))
+
+				// apply colorization if requested
+				if conf.Color(opts) {
+					sheet.Colorize(conf)
+				}
+
+				// display the cheatsheet
+				display.Display(display.Indent(sheet.Text), conf)
+			}
+		}
+
+		// exit early
+		os.Exit(0)
+	}
+
+	// otherwise, consolidate the cheatsheets found on all paths into a single
+	// map of `title` => `sheet` (ie, allow more local cheatsheets to override
+	// less local cheatsheets)
 	consolidated := sheets.Consolidate(cheatsheets)
 
 	// fail early if the requested cheatsheet does not exist