[discuss] doc: fix style for "markdown" documents

[membphis]

How about we use some tools to check the document style?

This plugin is nice: https://github.com/DavidAnson/vscode-markdownlint#configure

diff --git a/FAQ.md b/FAQ.md
index 166a8b04..e76c172c 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -19,11 +19,11 @@

 # FAQ

-##  Why a new API gateway?
+## Why a new API gateway

 There are new requirements for API gateways in the field of microservices: higher flexibility, higher performance requirements, and cloud native.

-##  What are the differences between APISIX and other API gateways?
+## What are the differences between APISIX and other API gateways

 APISIX is based on etcd to save and synchronize configuration, not relational databases such as Postgres or MySQL.

@@ -37,17 +37,17 @@ One of the goals of APISIX design and development is the highest performance in

 APISIX is the highest performance API gateway with a single-core QPS of 23,000, with an average delay of only 0.6 milliseconds.

-## Does APISIX have a console interface?
+## Does APISIX have a console interface

 Yes, in version 0.6 we have dashboard built in, you can operate APISIX through the web interface.

-## Can I write my own plugin?
+## Can I write my own plugin

 Of course, APISIX provides flexible custom plugins for developers and businesses to write their own logic.

 [How to write plugin](doc/plugin-develop.md)

-## Why we choose etcd as the configuration center?
+## Why we choose etcd as the configuration center
... ...

[sshniro]

That's a good idea @membphis , and we can also integrate the same rules in the CI/CD pipeline, so the docs comply with the rules.

[gxthrj]

aha，Let me try to do it