refactor: update tagline to TypeScript-style "Ruby with syntax for types"

- Change hero title from "Type-safe Ruby, the TypeScript way" to
  "T-Ruby is Ruby with syntax for types."
- Update subtitle to mention .rbs output and "Just like TypeScript"
- Update all i18n translations (ko, ja)

Author: yhk1038

docusaurus.config.ts

@@ -4,7 +4,7 @@ import type * as Preset from '@docusaurus/preset-classic';
 
 const config: Config = {
   title: 'T-Ruby',
-  tagline: 'Type-safe Ruby, the TypeScript way',
+  tagline: 'Ruby with syntax for types.',
   favicon: 'img/logo.svg',
 
   future: {

i18n/ja/code.json

@@ -212,11 +212,11 @@
     "description": "Hero title line 1"
   },
   "homepage.hero.titleHighlight": {
-    "message": "TypeScriptの方法で",
-    "description": "Hero title line 2 highlighted"
+    "message": "型構文を持つRubyです。",
+    "description": "Hero title highlighted text"
   },
   "homepage.hero.subtitle2": {
-    "message": "型アノテーション付きの.trbファイルを書きましょう。ランタイムオーバーヘッドなしで標準の.rbファイルにコンパイルします。",
+    "message": "型アノテーション付きの.trbファイルを書きましょう。標準の.rbファイルと.rbsにコンパイルします。TypeScriptのように。",
     "description": "Hero subtitle"
   },
   "homepage.install.command": {

i18n/ko/code.json

@@ -212,11 +212,11 @@
     "description": "Hero title line 1"
   },
   "homepage.hero.titleHighlight": {
-    "message": "TypeScript 방식으로",
-    "description": "Hero title line 2 highlighted"
+    "message": "타입 문법을 갖춘 Ruby입니다.",
+    "description": "Hero title highlighted text"
   },
   "homepage.hero.subtitle2": {
-    "message": "타입 어노테이션이 있는 .trb 파일을 작성하세요. 런타임 오버헤드 없이 표준 .rb 파일로 컴파일됩니다.",
+    "message": "타입 어노테이션이 있는 .trb 파일을 작성하세요. 표준 .rb 파일과 .rbs로 컴파일됩니다. 타입스크립트처럼요.",
     "description": "Hero subtitle"
   },
   "homepage.install.command": {

src/pages/index.tsx

@@ -39,14 +39,12 @@ function HeroBanner() {
           </a>
         </div>
         <Heading as="h1" className={styles.heroTitle}>
-          <Translate id="homepage.hero.title2">Type-safe Ruby,</Translate><br />
-          <span className={styles.heroHighlight}>
-            <Translate id="homepage.hero.titleHighlight">the TypeScript way</Translate>
-          </span>
+          T-Ruby is Ruby<br />
+          <span className={styles.heroHighlight}>with syntax for types.</span>
         </Heading>
         <p className={styles.heroSubtitle}>
           <Translate id="homepage.hero.subtitle2">
-            Write .trb files with type annotations. Compile to standard .rb files with zero runtime overhead.
+            Write .trb files with type annotations. Compile to standard .rb and .rbs files. Just like TypeScript.
           </Translate>
         </p>