inline help: scripts JSON API clarification (#9057)

* inline help: scripts JSON API clarification

While writing a forum response and trying to use `daml script` against
the JSON API, I was a bit confused by the existing help texts.

CHANGELOG_BEGIN
CHANGELOG_END

* thanks, scalafmt, that's very useful feedback

daml-script/runner/src/main/scala/com/digitalasset/daml/lf/engine/script/RunnerConfig.scala

@@ -54,12 +54,16 @@ object RunnerConfig {
     opt[String]("ledger-host")
       .optional()
       .action((t, c) => c.copy(ledgerHost = Some(t)))
-      .text("Ledger hostname")
+      .text(
+        "Ledger hostname. If --json-api is specified, this is used to connect to the JSON API and must include the protocol, e.g. \"http://localhost\"."
+      )
 
     opt[Int]("ledger-port")
       .optional()
       .action((t, c) => c.copy(ledgerPort = Some(t)))
-      .text("Ledger port")
+      .text(
+        "Ledger port. If --json-api is specified, this is the port used to connect to the JSON API."
+      )
 
     opt[File]("participant-config")
       .optional()
@@ -101,7 +105,7 @@ object RunnerConfig {
         c.copy(accessTokenFile = Some(Paths.get(f)))
       }
       .text(
-        "File from which the access token will be read, required to interact with an authenticated ledger"
+        "File from which the access token will be read, required to interact with an authenticated ledger or the JSON API."
       )
 
     TlsConfigurationCli.parse(this, colSpacer = "        ")((f, c) =>
@@ -112,7 +116,9 @@ object RunnerConfig {
       .action { (_, c) =>
         c.copy(jsonApi = true)
       }
-      .text("Run DAML Script via the HTTP JSON API instead of via gRPC.")
+      .text(
+        "Run DAML Script via the HTTP JSON API instead of via gRPC; use --ledger-host and --ledger-port for JSON API host and port. The JSON API requires an access token."
+      )
 
     opt[Int]("max-inbound-message-size")
       .action((x, c) => c.copy(maxInboundMessageSize = x))