docs(multi-url): improve documentation clarity and update examples

- Restructure multi-URL crawling documentation with better formatting and examples
- Update code examples to use new API syntax (arun_many)
- Add detailed parameter explanations for RateLimiter and Dispatchers
- Enhance CSS styling for better documentation readability
- Fix outdated method calls in feature demo script

BREAKING CHANGE: Updated dispatcher.run_urls() to crawler.arun_many() in examples

docs/md_v2/assets/styles.css

@@ -95,6 +95,10 @@ strong {
     
 }
 
+div.highlight {
+ margin-bottom: 2em;   
+}
+
 .terminal-card > header {
     color: var(--font-color);
     text-align: center;
@@ -231,6 +235,16 @@ pre {
     font-size: 2em;
 }
 
+.terminal h2 {
+    font-size: 1.5em;
+    margin-bottom: 0.8em;
+}
+
+.terminal h3 {
+    font-size: 1.3em;
+    margin-bottom: 0.8em;
+}
+
 .terminal h1, .terminal h2, .terminal h3, .terminal h4, .terminal h5, .terminal h6 {
     text-shadow: 0 0 0px var(--font-color), 0 0 0px var(--font-color), 0 0 0px var(--font-color);
 }