Fix: typos (ethereum#576)

* fix typo

* fix typo

* fix typo

* fix typo

Author: omahs

src/engine/common.md

@@ -161,7 +161,7 @@ Execution layer clients **MUST** support `engine_exchangeCapabilities` method, w
 
 #### Specification
 
-1. Consensus and execution layer client software **MAY** exchange with a list of currently supported Engine API methods. Execution layer client software **MUST NOT** log any error messages if this method has either never been called or haven't been called for a significant amount of time.
+1. Consensus and execution layer client software **MAY** exchange with a list of currently supported Engine API methods. Execution layer client software **MUST NOT** log any error messages if this method has either never been called or hasn't been called for a significant amount of time.
 
 2. Request and response lists **MUST** contain Engine API methods that are currently supported by consensus and execution client software respectively. Name of each method in both lists **MUST** include suffixed version. Consider the following examples:
     * Client software of both layers currently supports `V1` and `V2` versions of `engine_newPayload` method:

src/engine/paris.md

@@ -222,7 +222,7 @@ The payload build process is specified as follows:
 
     1. Verify that `payloadAttributes.timestamp` is greater than `timestamp` of a block referenced by `forkchoiceState.headBlockHash` and return `-38003: Invalid payload attributes` on failure.
 
-    2. If `payloadAttributes` passes all valdiation steps, begin a payload build process building on top of `forkchoiceState.headBlockHash` and identified via `buildProcessId` value. The build process is specified in the [Payload building](#payload-building) section.
+    2. If `payloadAttributes` passes all validation steps, begin a payload build process building on top of `forkchoiceState.headBlockHash` and identified via `buildProcessId` value. The build process is specified in the [Payload building](#payload-building) section.
 
     3. If `payloadAttributes` validation fails, the `forkchoiceState` update **MUST NOT** be rolled back.
 

src/engine/prague.md

@@ -184,7 +184,7 @@ The response of this method is updated with [`ExecutionPayloadBodyV2`](#executio
 * method: `engine_getPayloadBodiesByRangeV2`
 * params:
   1. `start`: `QUANTITY`, 64 bits - Starting block number
-  1. `count`: `QUANITTY`, 64 bits - Number of blocks to return
+  1. `count`: `QUANTITY`, 64 bits - Number of blocks to return
 * timeout: 10s
 
 #### Response

src/engine/shanghai.md

@@ -202,7 +202,7 @@ This method follows the same specification as [`engine_getPayloadV1`](./paris.md
 * method: `engine_getPayloadBodiesByRangeV1`
 * params:
   1. `start`: `QUANTITY`, 64 bits - Starting block number
-  1. `count`: `QUANITTY`, 64 bits - Number of blocks to return
+  1. `count`: `QUANTITY`, 64 bits - Number of blocks to return
 * timeout: 10s
 
 #### Response