message: update README for nodejs wrapper
diff: @@ -89,8 +89,14 @@ var verkey = await indy.abbreviateVerkey(did, fullVerkey)
  All the functions may yield an IndyError. The errors are based on libindy error codes defined [here](https://github.com/hyperledger/indy-sdk/blob/master/libindy/include/indy_mod.h).
  -* `err.indyCode` - the code number from libindy
  -* `err.indyName` - the name string for the code
  +* `err.indyCode`: Int - code number from libindy
  +* `err.indyName`: String - name for the error code
  +* `err.indyMessage`: String - human-readable error description
  +* `err.indyBacktrace`: String? - if enabled, this is the libindy backtrace string
  +
  +Collecting of backtrace can be enabled by:
  +1. Setting environment variable `RUST_BACKTRACE=1`
  +2. Calling [setRuntimeConfig](#setruntimeconfig--config-)(`{collect_backtrace: true}`)
  ### anoncreds
  @@ -2525,7 +2531,10 @@ Set libindy runtime configuration. Can be optionally called to change current pa
  * `config`: Json
  ```
  {
  - "crypto_thread_pool_size": <int> - size of thread pool for the most expensive crypto operations. (4 by default)
  + "crypto_thread_pool_size": Optional<int> - size of thread pool for the most expensive crypto operations. (4 by default)
  + "collect_backtrace": Optional<bool> - whether errors backtrace should be collected.
  + Capturing of backtrace can affect library performance.
  + NOTE: must be set before invocation of any other API functions.
  }
  ```
  