Use CLI flag values for string representations of "enum" values

I think this will make the output the easiest for the user to understand, and not require additional documentation
beyond what is required to explain the CLI.

configuration/checkmode/checkmode.go

@@ -32,8 +32,8 @@ const (
 	Strict                   Type = iota // strict
 	Specification                        // specification
 	Permissive                           // permissive
-	LibraryManagerSubmission             // --library-manager=submit
-	LibraryManagerIndexed                // --library-manager=update
+	LibraryManagerSubmission             // submit
+	LibraryManagerIndexed                // update
 	Official                             // ARDUINO_CHECK_OFFICIAL
 	Default                              // default
 )
@@ -54,11 +54,11 @@ var Types = map[Type]struct{}{
 // ComplianceModeFromString parses the --compliance flag value and returns the corresponding check mode settings.
 func ComplianceModeFromString(complianceModeString string) (bool, bool, bool, error) {
 	switch strings.ToLower(complianceModeString) {
-	case "strict":
+	case Strict.String():
 		return true, false, false, nil
-	case "specification":
+	case Specification.String():
 		return false, true, false, nil
-	case "permissive":
+	case Permissive.String():
 		return false, false, true, nil
 	default:
 		return false, false, false, fmt.Errorf("No matching compliance mode for string %s", complianceModeString)
@@ -68,9 +68,9 @@ func ComplianceModeFromString(complianceModeString string) (bool, bool, bool, er
 // LibraryManagerModeFromString parses the --library-manager flag value and returns the corresponding check mode settings.
 func LibraryManagerModeFromString(libraryManagerModeString string) (bool, bool, error) {
 	switch strings.ToLower(libraryManagerModeString) {
-	case "submit":
+	case LibraryManagerSubmission.String():
 		return true, false, nil
-	case "update":
+	case LibraryManagerIndexed.String():
 		return false, true, nil
 	case "false":
 		return false, false, nil

project/projecttype/projecttype.go

@@ -28,20 +28,20 @@ type Type int
 const (
 	Sketch       Type = iota // sketch
 	Library                  // library
-	Platform                 // boards platform
-	PackageIndex             // Boards Manager package index
-	All                      // any project type
+	Platform                 // platform
+	PackageIndex             // package-index
+	All                      // all
 	Not                      // N/A
 )
 
 // FromString parses the --project-type flag value and returns the corresponding project type.
 func FromString(projectTypeString string) (Type, error) {
 	projectType, found := map[string]Type{
-		"sketch":        Sketch,
-		"library":       Library,
-		"platform":      Platform,
-		"package-index": PackageIndex,
-		"all":           All,
+		Sketch.String():       Sketch,
+		Library.String():      Library,
+		Platform.String():     Platform,
+		PackageIndex.String(): PackageIndex,
+		All.String():          All,
 	}[strings.ToLower(projectTypeString)]
 
 	if found {

result/outputformat/outputformat.go

@@ -27,14 +27,14 @@ type Type int
 
 const (
 	Text Type = iota // text
-	JSON             // JSON
+	JSON             // json
 )
 
 // FromString parses the --format flag value and returns the corresponding output format type.
 func FromString(outputFormatString string) (Type, error) {
 	formatType, found := map[string]Type{
-		"text": Text,
-		"json": JSON,
+		Text.String(): Text,
+		JSON.String(): JSON,
 	}[strings.ToLower(outputFormatString)]
 
 	if found {