Update Limitations docs section

Author: kornilova203

docs/src/paradox/limitations/index.md

@@ -1,35 +1,47 @@
 # Limitations
 
-There are multiple unsupported cases that should be considered when generating bindings:
-
- 1. Currently bindgen does not support passing structs by value.  
-    For example, it will not be possible to call these two functions from Scala Native code:
-    
-    ```c
-    struct MyStruct {
-        int a;
-    };
-    
-    struct MyStruct returnStruct();
-    
-    void handleStruct(struct MyStruct mystr);
-    ```
-    To support such cases one should generate bindings for C wrapper functions that use pointers to structs instead of actual structs.
- 2. `#define`s for literals and variables are supported. For other types of `#define`s,
-    write wrapper functions that return defined values.
-    
-    ```c
-    // Supported
-    #define ESC 0x1b            /* Defines for numerical and string literals. */
-    extern const int pi_const;
-    #define PI pi_const         /* Defines aliasing extern variables. */
-
-    // Not supported (non-exhaustive list)
-    #define COLS      (getenv("COLS") ? atoi(getenv("COLS")) : 80)
-    #define MAX(a, b) (a > b ? a : b)
-    ```
-
- 3. There is no way to reuse already generated bindings.  
-    Bindgen outputs bindings also for headers that were included in a given header. See @github[#2](#2).
- 4. Type qualifiers `const`, `volatile` and `restrict` are not supported.
- 5. Extern variables are read-only. See @github[scala-native/scala-native#202](scala-native/scala-native#202).
+There are multiple unsupported cases that should be considered when generating bindings.
+
+## Passing structs by value
+
+Scala Native does not support passing structs by value, bindgen skips such functions.
+```c
+struct MyStruct {
+    int a;
+};
+
+struct MyStruct returnStruct(); // skipped
+
+void handleStruct(struct MyStruct mystr); // skipped
+```
+To support such cases one should generate bindings for C wrapper functions that use pointers to structs instead of
+actual structs.
+
+## Limited support of `#define`s
+
+`#define`s for literals and variables are supported. For other types of `#define`s,
+write wrapper functions that return defined values.
+
+```c
+// Supported
+#define ESC 0x1b            /* Defines for numerical and string literals. */
+extern const int pi_const;
+#define PI pi_const         /* Defines aliasing extern variables. */
+
+// Not supported (non-exhaustive list)
+#define COLS  (getenv("COLS") ? atoi(getenv("COLS")) : 80)
+#define MAX(a, b) (a > b ? a : b)
+```
+
+## Reusing generated bindings
+
+There is no way to reuse already generated bindings.  
+Bindgen outputs bindings also for headers that were included in a given header. See @github[#2](#2).
+
+## Type qualifiers
+
+Type qualifiers `const`, `volatile` and `restrict` are not supported.
+
+## Updating extern variables
+
+Extern variables are read-only. See @github[scala-native/scala-native#202](scala-native/scala-native#202).