doc: fix capitalization and image alt attributes (#4008)

Remove unneeded blank line

CODE_STYLE.md

@@ -21,7 +21,7 @@ title: APISIX Lua Coding Style Guide
 #
 -->
 
-## indentation
+## Indentation
 
 Use 4 spaces as an indent:
 

LICENSE

@@ -216,4 +216,3 @@ The following components are provided under the Apache License. See project link
 The text of each license is the standard Apache 2.0 license.
 
    ewma.lua file from kubernetes/ingress-nginx: https://github.com/kubernetes/ingress-nginx Apache 2.0
-

README.md

@@ -34,7 +34,7 @@ It can also be used as a [k8s ingress controller](https://github.com/apache/apis
 
 The technical architecture of Apache APISIX:
 
-![](docs/assets/images/apisix.png)
+![Technical architecture of Apache APISIX](docs/assets/images/apisix.png)
 
 ## Community
 

docs/es/latest/README.md

@@ -36,7 +36,7 @@ También puede usarse como [k8s ingress controller (control de ingreso)](https:/
 
 La arquitectura técnica de Apache APISIX:
 
-![](../../assets/images/apisix.png)
+![La arquitectura técnica de Apache APISIX](../../assets/images/apisix.png)
 
 ## Communidad
 

docs/zh/latest/README.md

@@ -34,7 +34,7 @@ title: Apache APISIX
 
 Apache APISIX 的技术架构如下图所示：
 
-![](../../assets/images/apisix.png)
+![Apache APISIX 的技术架构](../../assets/images/apisix.png)
 
 ## 社区
 

kubernetes/README.md

@@ -17,7 +17,7 @@
 #
 -->
 
-### kubernetes
+### Kubernetes
 
 There are some yaml files for deploying apisix in Kubernetes.
 
@@ -35,7 +35,7 @@ if you do not need to change any config, and use default config in `../conf/conf
 $ kubectl create configmap apisix-gw-config.yaml --from-file=../conf/config.yaml
 ```
 
-#### when using etcd-operator
+#### When using etcd-operator
 
 when using etcd-operator, you need to change `apisix-gw-config-cm.yaml`: