docs: fix spelling mistakes and grammatical errors (#4423)

Fixed many grammatical errors as well a couple of spelling
errors in faq.md in english language under en directory.

docs/source/en/faq.md

@@ -8,7 +8,7 @@ If you have questions that is not contained below, please check [Egg issues](htt
 Thank you for reporting an issue.
 
 1. It's RECOMMENDED to submit PR for typo or tiny bug fix.
-2. If this's a FEATURE request, please provide: details, pseudo codes if necessary.
+2. If this's a FEATURE request, please provide: details, pseudo-codes if necessary.
 3. If this's a BUG, please provide: course repetition, error log and configuration. Fill in as much of the template below as you're able.
 4. **It will be nice to use `npm init egg --type=simple bug` to provide a mini GitHub repository which can reproduce the issue.**
 
@@ -21,7 +21,7 @@ Framework [Config](./basics/config.md) settings is powerfull, support different
 
 When you got some trouble, and want to find out what is the final config using at runtime, you can checkout `${root}/run/application_config.json`(workers' configurations) and `${root}/run/agent_config.json`(agent's configurations).(`root` is application's root directory, in `local` and `unittest` environments, it will be project base directory, in other environments will be HOME directory)
 
-Please make sure you don't make mistake like the code below:
+Please make sure you don't make a mistake like the code below:
 
 ```js
 // config/config.default.js
@@ -35,19 +35,19 @@ module.exports = appInfo => {
 
 ## Where are my log files in prod environment?
 
-By default, logs will print at `${baseDir}/logs`(baseDir is project's base directory) in local environment.But in non-development environments(neither local nor unittest), the logs will print at `$HOME/logs`(such as `/home/admin/logs`). So the logs won't mix in during development and locate in the same place when run in production environment.
+By default, logs will print at `${baseDir}/logs`(baseDir is project's base directory) in the local environment. But in non-development environments(neither local nor unittest), the logs will print at `$HOME/logs`(such as `/home/admin/logs`). So the logs won't mix in during development and locate in the same place when run in production environment.
 
 ## Why not choose `PM2` as the process management tool?
 
 1. `PM2` itself is too complex to issue problems if any.
-2. Deep optimization could be difficlut to achieve if choosing PM2.
-3. Pattern like one leader process communicating with remote services, along with serveral follower processes delegating request to it ([Cluster](./core/cluster-and-ipc.md)), is a rigid demand for reducing connections and data exchange load, espeically when facing applications in very large scale. egg originates from Ant Financial Group and Alibaba Group, we start with applications in that scale at first, so we take these goals into consideration. All of these goals above could be hard to achieve with PM2.
+2. Deep optimization could be difficult to achieve if choosing PM2.
+3. Pattern like one leader process communicating with remote services, along with several follower processes delegating the request to it ([Cluster](./core/cluster-and-ipc.md)), is a rigid demand for reducing connections and data exchange load, especially when facing applications in very large scale. egg originates from Ant Financial Group and Alibaba Group, we start with applications in that scale at first, so we take these goals into consideration. All of these goals above could be hard to achieve with PM2.
 
-Process management is very important. It defines the way we write code, meanwhile relates to deep runtime optimizations. So we think it's better included in framework itself.
+Process management is very important. It defines the way we write code, meanwhile relates to deep runtime optimizations. So we think it's better included in the framework itself.
 
 **How to start application with PM2?**
 
-Although PM2 is not recommanded, you can use it anyway.
+Although PM2 is not recommended, you can use it anyway.
 
 Firstly, put a start file in the root directory of your project:
 
@@ -62,7 +62,7 @@ egg.startCluster({
 });
 ```
 
-We can start application with PM2 like this:
+We can start the application with PM2 like this:
 
 ```bash
 pm2 start server.js
@@ -77,9 +77,9 @@ There are two kinds of common csrf errors:
 
 By default [egg-security](https://github.com/eggjs/egg-security/) plugin built in Egg requires CSRF validation against all 'unsafe' request such as `POST`, `PUT`, `DELETE` requests.
 
-The error will disappear in the presence of correct csrf token in request. For more implentation details, see [./core/security.md#csrf].
+The error will disappear in the presence of the correct csrf token in the request. For more implementation details, see [./core/security.md#csrf].
 
-## In local development Environment, why is worker process not restarted automatically when files are modified?
+## In the local development Environment, why is the worker process not restarted automatically when files are modified?
 
 Usually this happens when you are using Jetbrains softwares(IntelliJ IDEA, WebStorm, etc.) with `Safe Write` turned on.