Doc/improve mermaid chart (open-telemetry#404)

README.md

@@ -45,7 +45,7 @@ emailservice(Email Service):::ruby
 frontend(Frontend):::javascript
 loadgenerator([Load Generator]):::python
 paymentservice(Payment Service):::javascript
-productcatalogservice(ProductCatalog Service):::golang
+productcatalogservice(Product Catalog Service):::golang
 quoteservice(Quote Service):::php
 recommendationservice(Recommendation Service):::python
 shippingservice(Shipping Service):::rust
@@ -55,24 +55,24 @@ featureflagstore[(Feature Flag Store<br/>&#40PostgreSQL DB&#41)]
 Internet -->|HTTP| frontend
 loadgenerator -->|HTTP| frontend
 
-checkoutservice --> cartservice --> cache
-checkoutservice --> productcatalogservice
-checkoutservice --> currencyservice
-checkoutservice -->|HTTP| emailservice
-checkoutservice --> paymentservice
-checkoutservice --> shippingservice
+checkoutservice --->|gRPC| cartservice --> cache
+checkoutservice --->|gRPC| productcatalogservice
+checkoutservice --->|gRPC| currencyservice
+checkoutservice --->|HTTP| emailservice
+checkoutservice --->|gRPC| paymentservice
+checkoutservice -->|gRPC| shippingservice
 
-frontend --> adservice
-frontend --> cartservice
-frontend --> productcatalogservice
-frontend --> checkoutservice
-frontend --> currencyservice
-frontend --> recommendationservice --> productcatalogservice
-frontend --> shippingservice -->|HTTP| quoteservice
+frontend -->|gRPC| adservice
+frontend -->|gRPC| cartservice
+frontend -->|gRPC| productcatalogservice
+frontend -->|gRPC| checkoutservice
+frontend -->|gRPC| currencyservice
+frontend -->|gRPC| recommendationservice -->|gRPC| productcatalogservice
+frontend -->|gRPC| shippingservice -->|HTTP| quoteservice
 
-productcatalogservice --> |evalFlag| featureflagservice
+productcatalogservice -->|gRPC| featureflagservice
 
-shippingservice --> |evalFlag| featureflagservice
+shippingservice -->|gRPC| featureflagservice
 
 featureflagservice --> featureflagstore