docs: update kcl-lang Rust documents

Signed-off-by: peefy <[email protected]>

README.md

@@ -5,25 +5,24 @@
 ### How to Use
 
 ```shell
-cargo add kcl
+cargo add kcl-lang
 ```
 
 Write the Code
 
 ```rust
 use kcl_lang::*;
-use std::path::Path;
 use anyhow::Result;
 
 fn main() -> Result<()> {
     let api = API::new()?;
     let args = &ExecProgramArgs {
-        work_dir: Path::new(".").join("src").join("testdata").canonicalize().unwrap().display().to_string(),
-        k_filename_list: vec!["test.k".to_string()],
+        k_filename_list: vec!["main.k".to_string()],
+        k_code_list: vec!["a = 1".to_string()],
         ..Default::default()
     };
     let exec_result = api.exec_program(args)?;
-    assert_eq!(exec_result.yaml_result, "alice:\n  age: 18");
+    println!("{}", exec_result.yaml_result);
     Ok(())
 }
 ```