Always force hash directives on a new line. (#600)

Fixes #576

src/Fantomas.Tests/CompilerDirectivesTests.fs

@@ -1006,4 +1006,46 @@ let foo =
     |> List.rev
 #endif
     |> List.sort
+"""
+
+[<Test>]
+let ``async block inside directive, 576`` () =
+    formatSourceString false """#if TEST
+let f () =
+    async {
+        let x = 2
+        return x
+    }
+#endif
+"""  config
+    |> prepend newline
+    |> should equal """
+#if TEST
+let f() =
+    async {
+        let x = 2
+        return x
+    }
+#endif
+"""
+
+[<Test>]
+let ``async block inside directive, TEST`` () =
+    formatSourceStringWithDefines ["TEST"] """#if TEST
+let f () =
+    async {
+        let x = 2
+        return x
+    }
+#endif
+"""  config
+    |> prepend newline
+    |> should equal """
+#if TEST
+let f() =
+    async {
+        let x = 2
+        return x
+    }
+#endif
 """

src/Fantomas.Tests/RecordTests.fs

@@ -67,7 +67,8 @@ type Element =
 module RecordSignature
 /// Represents simple XML elements.
 type Element =
-    { /// The attribute collection.
+    {
+      /// The attribute collection.
       Attributes: IDictionary<Name, string>;
 
       /// The children collection.

src/Fantomas/Context.fs

@@ -513,7 +513,7 @@ let internal printTriviaContent (c: TriviaContent) (ctx: Context) =
     // It is hard to always get this right in CodePrinter, so we detect it based on the current code.
     let addNewline =
         currentLastLine
-        |> Option.map(fun line -> line.Trim().Length > 1)
+        |> Option.map(fun line -> line.Trim().Length > 0)
         |> Option.defaultValue false
 
     let addSpace =