fix: variable name (#1621)

Author: ccarruitero

docs/altimeter-mpl3115a2.md

@@ -33,7 +33,7 @@ const { Altimeter, Board } = require("../");
 const board = new Board();
 
 board.on("ready", () => {
-  const altitude = new Altimeter({
+  const altimeter = new Altimeter({
     controller: "MPL3115A2",
     // Change `elevation` with whatever is reported
     // on http://www.whatismyelevation.com/.

eg/altimeter-mpl3115a2.js

@@ -2,7 +2,7 @@ const { Altimeter, Board } = require("../");
 const board = new Board();
 
 board.on("ready", () => {
-  const altitude = new Altimeter({
+  const altimeter = new Altimeter({
     controller: "MPL3115A2",
     // Change `elevation` with whatever is reported
     // on http://www.whatismyelevation.com/.