doc: update prebuild_tools.md

PR-URL: nodejs/node-addon-api#527
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: NickNaso <nicoladelgobbo@gmail.com>

doc/prebuild_tools.md

@@ -9,7 +9,7 @@ possible to ditribute the native add-on in pre-built form for different platform
 and architectures. The prebuild tools help to create and distrubute the pre-built
 form of a native add-on.
 
-The following list report two of the tools that are compatible with **N-API**:
+The following list report known tools that are compatible with **N-API**:
 
 - **[node-pre-gyp](https://www.npmjs.com/package/node-pre-gyp)**
 - **[prebuild](https://www.npmjs.com/package/prebuild)**