fix: doc drift

Author: Ludo Galabru

README.md

@@ -147,7 +147,7 @@ The current `bitcoin` predicates supports the following `if_this` constructs:
 {
     "if_this": {
         "scope": "stacks_protocol",
-        "operation": "stx_transfered"
+        "operation": "stx_transferred"
     }
 }
 

docs/how-to-guides/how-to-use-chainhook-with-bitcoin.md

@@ -172,7 +172,7 @@ Get any transaction, including an STX transfer operation
 {
     "if_this": {
         "scope": "stacks_protocol",
-        "operation": "stx_transfered"
+        "operation": "stx_transferred"
     }
 }
 ```

docs/how-to-guides/how-to-use-chainhook-with-stacks.md

@@ -150,7 +150,7 @@ Get any transaction, including an STX transfer operation
 {
     "if_this": {
         "scope": "stacks_protocol",
-        "operation": "stx_transfered"
+        "operation": "stx_transferred"
     }
 }
 ```