refactor(compiler): simplify language extraction logic

Remove redundant `let` block and directly access `virtualFile` for language extraction in `File

Author: phodal

exts/devins-lang/src/main/kotlin/cc/unitmesh/devti/language/compiler/exec/FileInsCommand.kt

@@ -44,9 +44,7 @@ class FileInsCommand(private val myProject: Project, private val prop: String) :
 
         InsCommandListener.notify(this, InsCommandStatus.SUCCESS, virtualFile)
 
-        val lang = virtualFile.let {
-            PsiManager.getInstance(myProject).findFile(it!!)?.language?.displayName
-        } ?: ""
+        val lang = PsiManager.getInstance(myProject).findFile(virtualFile)?.language?.displayName ?: ""
 
         contentsToByteArray.let { bytes ->