docs: Fixes #154 (#167)

* Move triple backticks onto new line so it doesn't break the code snippet formatting

* Add newline between dependency imports and variable declarations

* Add link to relevant line of Github repo of eventemitter3 instead of the travis build directory

* Add full stop at end of sentence in line before `@example` in .ts files, since I noticed that was the only difference between code snippet in docs that was being rendered correctly and one that was not (if the docs were generated from it). Not sure if this actually makes any difference though, but it doesn't hurt to try. i.e. change `[[unsubscribe]]` to `[[unsubscribe]].`

* Add missing code syntax for `new Ws(defaults.WS_URL)`

* Add missing `*__example__*:`

* Add missing semi-colons throughout code

* Fix typos and some grammar

* Move import of external libraries i.e. `const BN = require('bn.js');` or `const crypto = require('crypto');` before `@polkadot` ones in code

* Change from `e` to `error` in catch blocks for readable documentation

docs/examples/01_simple_connect/index.js

@@ -1,16 +1,16 @@
-const Api = require('@polkadot/api').default
-const WsProvider = require('@polkadot/api-provider/ws').default
-const provider = new WsProvider('ws://127.0.0.1:9944')
-const api = new Api(provider)
+const Api = require('@polkadot/api').default;
+const WsProvider = require('@polkadot/api-provider/ws').default;
+const provider = new WsProvider('ws://127.0.0.1:9944');
+const api = new Api(provider);
 
 async function getChain () {
-  return api.system.chain()
+  return api.system.chain();
 }
 
 async function main () {
-  const chain = await getChain()
+  const chain = await getChain();
 
-  console.log('You are connected to chain:', chain)
+  console.log('You are connected to chain:', chain);
 }
 
-main().finally(_ => process.exit())
+main().finally(_ => process.exit());