simulateTransaction allows executing read-only functions for free (#1664)

* Clarify that simulateTransaction allows executing read-only functions for free

* Add a note to the RPC specfile, as well

---------

Co-authored-by: Elliot <elliot@stellar.org>

Author: briwylde08

docs/data/apis/rpc/api-reference/methods/simulateTransaction.mdx

@@ -12,6 +12,12 @@ import rpcSpec from "@site/static/stellar-rpc.openrpc.json";
   }
 />
 
+:::note
+
+`simulateTransaction` can also invoke read-only functions for free.
+
+:::
+
 ### Using the Lab
 
 The `simulateTransaction` method allows you to **simulate a smart contract invocation** without actually submitting it to the network. It’s a powerful tool for testing and debugging transactions safely.

openrpc/src/stellar-rpc/methods/simulateTransaction.json

@@ -1,7 +1,7 @@
 {
     "name": "simulateTransaction",
     "summary": "submits a trial contract invocation transaction",
-    "description": "Submit a trial contract invocation to simulate how it would be executed by the network. This endpoint calculates the effective transaction data, required authorizations, and minimal resource fee. It provides a way to test and analyze the potential outcomes of a transaction without actually submitting it to the network.",
+    "description": "Submit a trial contract invocation to simulate how it would be executed by the network. This endpoint calculates the effective transaction data, required authorizations, and minimal resource fee. It provides a way to test and analyze the potential outcomes of a transaction without actually submitting it to the network.\n\nThis method can also be used to invoke read-only smart contract functions for free.",
     "externalDocs": {
         "url": "https://developers.stellar.org/docs/data/apis/rpc/api-reference/methods/simulateTransaction"
     },

static/stellar-rpc.openrpc.json

@@ -1184,7 +1184,7 @@
             },
             "events": {
               "type": "object",
-              "description": "Contains all events emitted during transaction execution.\n\n_Note: Available only on Protocol 23+ (currently testnet only)._",
+              "description": "Contains all events emitted during transaction execution.\n\n_Note: Available only on RPC v23.x (currently testnet only)._",
               "properties": {
                 "transactionEventsXdr": {
                   "type": "array",
@@ -1429,7 +1429,7 @@
                   },
                   "events": {
                     "type": "object",
-                    "description": "Contains all events emitted during transaction execution.\n\n_Note: Available only on Protocol 23+ (currently testnet only)._",
+                    "description": "Contains all events emitted during transaction execution.\n\n_Note: Available only on RPC v23.x (currently testnet only)._",
                     "properties": {
                       "transactionEventsXdr": {
                         "type": "array",
@@ -2134,7 +2134,7 @@
     {
       "name": "simulateTransaction",
       "summary": "submits a trial contract invocation transaction",
-      "description": "Submit a trial contract invocation to simulate how it would be executed by the network. This endpoint calculates the effective transaction data, required authorizations, and minimal resource fee. It provides a way to test and analyze the potential outcomes of a transaction without actually submitting it to the network.",
+      "description": "Submit a trial contract invocation to simulate how it would be executed by the network. This endpoint calculates the effective transaction data, required authorizations, and minimal resource fee. It provides a way to test and analyze the potential outcomes of a transaction without actually submitting it to the network.\n\nThis method can also be used to invoke read-only smart contract functions for free.",
       "externalDocs": {
         "url": "https://developers.stellar.org/docs/data/apis/rpc/api-reference/methods/simulateTransaction"
       },