message: Fix PostTxResult/assertIsPostTxSuccess -> BroadcastTxResult/assertIsBroadcastTxResult
diff: @@ -123,9 +123,9 @@ Those can be signed and broadcast the manual way or by using a higher level
  ```ts
  import {
  coins,
  + BroadcastTxResult,
  MsgSubmitProposal,
  OfflineSigner,
  - PostTxResult,
  SigningCosmosClient,
  StdFee,
  } from "@cosmjs/launchpad";
  @@ -133,7 +133,7 @@ import {
  async function publishProposal(
  apiUrl: string,
  signer: OfflineSigner,
  -): Promise<PostTxResult> {
  +): Promise<BroadcastTxResult> {
  const [{ address: authorAddress }] = await signer.getAccounts();
  const memo = "My first proposal on chain";
  @@ -171,7 +171,7 @@ example we show how to build a client for a blockchain with a wasm module:
  ```ts
  import { MsgExecuteContract, setupWasmExtension } from "@cosmjs/cosmwasm";
  import {
  - assertIsPostTxSuccess,
  + assertIsBroadcastTxResult,
  LcdClient,
  makeSignDoc,
  setupAuthExtension,
  @@ -208,8 +208,8 @@ const { account_number, sequence } = (
  const signDoc = makeSignDoc([msg], fee, apiUrl, memo, account_number, sequence);
  const { signed, signature } = await signer.sign(myAddress, signDoc);
  const signedTx = makeStdTx(signed, signature);
  -const result = await client.postTx(signedTx);
  -assertIsPostTxSuccess(result);
  +const result = await client.broadcastTx(signedTx);
  +assertIsBroadcastTxResult(result);
  ```
  ## Secure key storage
  