Fix some golint errors

category.go

@@ -1,5 +1,6 @@
 package cli
 
+// CommandCategories interface allows for category manipulation
 type CommandCategories interface {
 	// AddCommand adds a command to a category, creating a new category if necessary.
 	AddCommand(category string, command *Command)

errors.go

@@ -48,6 +48,7 @@ func (m *multiError) Errors() []error {
 	return errs
 }
 
+// ErrorFormatter is the interface that will suitably format the error output
 type ErrorFormatter interface {
 	Format(s fmt.State, verb rune)
 }

flag_path.go

@@ -72,7 +72,7 @@ func (f *PathFlag) Apply(set *flag.FlagSet) error {
 	return nil
 }
 
-// String looks up the value of a local PathFlag, returns
+// Path looks up the value of a local PathFlag, returns
 // "" if not found
 func (c *Context) Path(name string) string {
 	if fs := lookupFlagSet(name, c); fs != nil {

help.go

@@ -138,7 +138,7 @@ func printFlagSuggestions(lastArg string, flags []Flag, writer io.Writer) {
 		if bflag, ok := flag.(*BoolFlag); ok && bflag.Hidden {
 			continue
 		}
-		for _, name := range flag.Names(){
+		for _, name := range flag.Names() {
 			name = strings.TrimSpace(name)
 			// this will get total count utf8 letters in flag name
 			count := utf8.RuneCountInString(name)