doc: add missing API docs

Signed-off-by: Alexander Bezzubov <[email protected]>

Author: bzz

README.md

@@ -6,7 +6,7 @@ generation and [libuast](https://github.com/bblfsh/libuast) for XPath queries.
 
 ### Status
 
-Latest`scala-client` v2.x supports [UASTv2 protocol](https://doc.bblf.sh/uast/uast-specification-v2.html).
+The latest `scala-client` *v2.x* supports the [UASTv2 protocol](https://doc.bblf.sh/uast/uast-specification-v2.html).
 
 ### Installation
 

src/main/native/org_bblfsh_client_v2_libuast_Libuast.cc

@@ -401,12 +401,16 @@ class Node : public uast::Node<Node *> {
   }
 };
 
+// Custom comparator for keys in std::map<object>.
+// Compares actual objects instead of JNI references.
 struct EqByObj {
   bool operator()(jobject a, jobject b) const {
     return getJNIEnv()->IsSameObject(a, b);
   }
 };
 
+// Custom hasing function for keys in std::map<object>.
+// Deligates actual hasing to the managed .hashCode() impl.
 struct HashByObj {
   std::size_t operator()(jobject obj) const noexcept {
     auto hash = IntMethod(getJNIEnv(), "hashCode", "()I", CLS_OBJ, obj);