more fixed for documentation files (#2016)

CONCURRENCY.md

@@ -1,9 +1,3 @@
----
-type: doc
-layout: reference
-title: "Concurrency in Kotlin/Native"
----
-
 ### Concurrency in Kotlin/Native
 
   Kotlin/Native runtime doesn't encourage a classical thread-oriented concurrency
@@ -60,8 +54,8 @@ title: "Concurrency in Kotlin/Native"
   For more complete example please refer to the [workers example](https://github.com/JetBrains/kotlin-native/tree/master/samples/workers)
  in the Kotlin/Native repository.
 
-
-## <a name="transfer"></a>Object transfer and freezing
+<a name="transfer"></a>
+## Object transfer and freezing
 
    Important invariant that Kotlin/Native runtime maintains is that object is either owned by a single
   thread/worker, or is immutable (_shared XOR mutable_). This ensures that the same data has a single mutator, and so no need for
@@ -82,7 +76,8 @@ title: "Concurrency in Kotlin/Native"
  is allowed. Currently, Kotlin/Native runtime only freezes enum objects after creation, although additional
  autofreezing of certain provably immutable objects could be implemented in the future.
 
-## <a name="detach"></a>Object subgraph detachment
+<a name="detach"></a>
+## Object subgraph detachment
 
    Object subgraph without external references could be disconnected using `detachObjectGraph` to
   a `COpaquePointer` value, which could be stored in `void*` data, so disconnected object subgraphs
@@ -90,7 +85,8 @@ title: "Concurrency in Kotlin/Native"
   or worker. Combined with [raw memory sharing](#shared) it allows side channel object transfer between
   concurrent threads, if worker mechanisms are insufficient for the particular task.
 
-## <a name="shared"></a>Raw shared memory
+<a name="shared"></a>
+## Raw shared memory
 
   Considering strong ties of Kotlin/Native with C via interoperability, in conjunction with other mechanisms
  mentioned above one could build popular data structures, like concurrent hashmap or shared cache with
@@ -118,7 +114,8 @@ class SharedData(rawPtr: NativePtr) : CStructVar(rawPtr) {
 So combined with the top level variable declared above, it allows seeing the same memory from different
 threads and building traditional concurrent structures with platform-specific synchronization primitives.
 
-## <a name="top_level"></a>Global variables and singletons
+<a name="top_level"></a>
+## Global variables and singletons
 
   Frequently, global variables are a source of unintended concurrency issues, so _Kotlin/Native_ implements
 following mechanisms to prevent unintended sharing of state via global objects: