fixed logic issue when flattening interpolation which resulted in missing content

Author: RandomHashTags

Sources/HTMLKitMacros/HTMLElement.swift

@@ -296,7 +296,7 @@ private extension HTMLElement {
         let interpolation:[ExpressionSegmentSyntax] = expression.stringLiteral?.segments.compactMap({ $0.as(ExpressionSegmentSyntax.self) }) ?? []
         var remaining_interpolation:Int = interpolation.count
         for expr in interpolation {
-            string = flatten_interpolation(context: context, remaining_interpolation: &remaining_interpolation, expr: expr)
+            string.replace("\(expr)", with: flatten_interpolation(context: context, remaining_interpolation: &remaining_interpolation, expr: expr))
         }
         if returnType == .interpolation || remaining_interpolation > 0 {
             if !string.contains("\\(") {

Tests/HTMLKitTests/HTMLKitTests.swift

@@ -299,6 +299,28 @@ extension HTMLKitTests {
         let test:[Int] = [1]
         bro = #area(coords: test)
     }*/
+
+
+    @Test func interpolation_flattening() {
+        let title:String = "flattening"
+        var string:String = #meta(content: "\("interpolation \(title)")", name: "description")
+        #expect(string == "<meta content=\"interpolation \(title)\" name=\"description\">")
+
+        string = #meta(content: "interpolation \(title)", name: "description")
+        #expect(string == "<meta content=\"interpolation \(title)\" name=\"description\">")
+
+        string = #meta(content: "interpolation\(title)", name: "description")
+        #expect(string == "<meta content=\"interpolation\(title)\" name=\"description\">")
+
+        string = #meta(content: "\(title) interpolation", name: "description")
+        #expect(string == "<meta content=\"flattening interpolation\" name=\"description\">")
+
+        string = #meta(content: "\(title)interpolation", name: "description")
+        #expect(string == "<meta content=\"flatteninginterpolation\" name=\"description\">")
+
+        string = #meta(content: "\(title)\("interpolation")", name: "description")
+        #expect(string == "<meta content=\"flatteninginterpolation\" name=\"description\">")
+    }
 }
 
 // MARK: Attribute tests