[Gradle] Remove & deprecate file extensions string constants

^KT-75760
diff --git a/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/GradleNodeModuleBuilder.kt b/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/GradleNodeModuleBuilder.kt
index 8ff9c3a..792d5e4 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/GradleNodeModuleBuilder.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/GradleNodeModuleBuilder.kt
@@ -21,7 +21,7 @@
     val moduleName: String,
     val moduleVersion: String,
     val srcFiles: Collection<File>,
-    val cacheDir: File
+    val cacheDir: File,
 ) {
     private var srcPackageJsonFile: File? = null
     private val files = mutableListOf<File>()
@@ -64,10 +64,12 @@
             version = version ?: moduleVersion
         } ?: PackageJson(moduleName, moduleVersion)
 
-        val metaFiles = files.filter { it.name.endsWith(".$META_JS") }
+        val metaJsExt = ".meta.js"
+
+        val metaFiles = files.filter { it.name.endsWith(metaJsExt) }
         if (metaFiles.size == 1) {
             val metaFile = metaFiles.single()
-            val name = metaFile.name.removeSuffix(".$META_JS")
+            val name = metaFile.name.removeSuffix(metaJsExt)
             packageJson.name = name
             packageJson.main = "${name}.js"
         }
@@ -95,9 +97,9 @@
 private fun isKotlinJsRuntimeFile(file: File): Boolean {
     if (!file.isFile) return false
     val name = file.name
-    return name.endsWith(".$JS")
-            || name.endsWith(".$MJS")
-            || name.endsWith(".$WASM")
-            || name.endsWith(".$JS_MAP")
-            || name.endsWith(".$HTML")
-}
\ No newline at end of file
+    return name.endsWith(".js")
+            || name.endsWith(".mjs")
+            || name.endsWith(".wasm")
+            || name.endsWith(".js.map")
+            || name.endsWith(".html")
+}
diff --git a/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/utils.kt b/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/utils.kt
index 30dd90f..3558c63 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/utils.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/utils.kt
@@ -62,11 +62,22 @@
     return hasher.hash().toByteArray().toHex()
 }
 
+@Deprecated("Unused string constant. Scheduled for removal in Kotlin 2.4.", ReplaceWith(""""js""""))
 const val JS = "js"
+
+@Deprecated("Unused string constant. Scheduled for removal in Kotlin 2.4.", ReplaceWith(""""mjs""""))
 const val MJS = "mjs"
+
+@Deprecated("Unused string constant. Scheduled for removal in Kotlin 2.4.", ReplaceWith(""""wasm""""))
 const val WASM = "wasm"
+
+@Deprecated("Unused string constant. Scheduled for removal in Kotlin 2.4.", ReplaceWith(""""js.map""""))
 const val JS_MAP = "js.map"
+
+@Deprecated("Unused string constant. Scheduled for removal in Kotlin 2.4.", ReplaceWith(""""meta.js""""))
 const val META_JS = "meta.js"
+
+@Deprecated("Unused string constant. Scheduled for removal in Kotlin 2.4.", ReplaceWith(""""html""""))
 const val HTML = "html"
 
 internal fun writeWasmUnitTestRunner(workingDir: File, compiledFile: File): File {