chore(server): update env example and docs (#9153)

docs/developing-server.md

@@ -7,7 +7,7 @@ This document explains how to start server (@affine/server) locally with Docker
 
 ## Run required dev services in docker compose
 
-```
+```sh
 cp ./.docker/dev/compose.yml.example ./.docker/dev/compose.yml
 cp ./.docker/dev/.env.example ./.docker/dev/.env
 
@@ -16,16 +16,17 @@ docker compose -f ./.docker/dev/compose.yml up -d
 
 ## Build native packages (you need to setup rust toolchain first)
 
-```
+```sh
 # build native
 yarn workspace @affine/server-native build
 ```
 
 ## Prepare dev environment
 
-```
+```sh
 cd packages/backend/server
 
+# uncomment all env variables here
 cp .env.example .env
 yarn prisma db push
 yarn data-migration run
@@ -33,7 +34,7 @@ yarn data-migration run
 
 ## Start server
 
-```
+```sh
 yarn dev
 ```
 
@@ -45,7 +46,7 @@ when server started, it will created a default user for testing:
 
 ## Start frontend
 
-```
+```sh
 # at project root
 yarn dev
 ```
@@ -58,7 +59,7 @@ Now you should be able to start developing affine with server enabled.
 
 ### Enable prisma studio (Database GUI)
 
-```
+```sh
 # available at http://localhost:5555
 yarn prisma studio
 ```