x/wasihttp/examples: add proxy and roundtrip WIT packages to examples

and update the examples docs to refer to the right working directory and
command to build.

Signed-off-by: Jiaxiao Zhou <[email protected]>

Author: Mossaka

x/wasihttp/examples/basic/basic.go

@@ -1,6 +1,7 @@
 // This example implements a basic web server.
 //
-// To run: `tinygo run -target=wasip2-http.json ./examples/basic`
+// working direcotry: "./x/wasihttp/examples"
+// To run: `tinygo run -target=wasip2-http.json ./basic`
 // Test /: `curl -v 'http://0.0.0.0:8080/'`
 // Test /error: `curl -v 'http://0.0.0.0:8080/error'`
 

x/wasihttp/examples/counter/counter.go

@@ -1,7 +1,8 @@
 // This example implements a web server with a counter running in a goroutine.
 // This demonstrates instance reuse by the host.
 //
-// To run: `tinygo run -target=wasip2-http.json ./examples/counter`
+// working directory: "./x/wasihttp/examples"
+// To run: `tinygo run -target=wasip2-http.json ./counter`
 // Test /: `curl -v 'http://0.0.0.0:8080/'`
 
 package main