Compress the languages data (#468)

There is a lot of repeated content in languages.json, so using
gzip compression can significantly reduce the size of the compiled
binary file.

On my windows machine with go1.22, it shows:

- "processor/constants.go": 170k -> 20k, 150k reduced.
- scc binary file: 8909k -> 8836.5k, 72.5k reduced.

Gzip is very fast, as hyperfine reports there's nearly no harm on
the performance.

processor/processor.go

@@ -3,6 +3,8 @@
 package processor
 
 import (
+	"bytes"
+	"compress/gzip"
 	"encoding/base64"
 	"fmt"
 	"os"
@@ -504,13 +506,17 @@ func loadDatabase() map[string]Language {
 	var database map[string]Language
 	startTime := makeTimestampMilli()
 
-	data, err := base64.StdEncoding.DecodeString(languages)
+	gzData, err := base64.StdEncoding.DecodeString(languages)
 	if err != nil {
 		panic(fmt.Sprintf("failed to base64 decode languages: %v", err))
 	}
+	dataReader, err := gzip.NewReader(bytes.NewReader(gzData))
+	if err != nil {
+		panic(fmt.Sprintf("failed to create gzip reader: %v", err))
+	}
 
 	var json = jsoniter.ConfigCompatibleWithStandardLibrary
-	if err := json.Unmarshal(data, &database); err != nil {
+	if err := json.NewDecoder(dataReader).Decode(&database); err != nil {
 		panic(fmt.Sprintf("languages json invalid: %v", err))
 	}
 

scripts/include.go

@@ -3,6 +3,7 @@
 package main
 
 import (
+	"compress/gzip"
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
@@ -50,9 +51,11 @@ func generateConstants() error {
 			out.Write([]byte(strings.TrimSuffix(f.Name(), ".json") + " = `"))
 
 			enc := base64.NewEncoder(base64.StdEncoding, out)
-			if _, err := io.Copy(enc, f); err != nil {
+			gz, _ := gzip.NewWriterLevel(enc, gzip.BestSpeed)
+			if _, err := io.Copy(gz, f); err != nil {
 				return fmt.Errorf("failed to encode file '%s': %v", f.Name(), err)
 			}
+			gz.Close()
 			enc.Close()
 
 			out.Write([]byte("`\n"))