Apply suggestions from code review

Co-authored-by: Heitor Tashiro Sergent <heitortsergent@gmail.com>

Author: mstoykov

docs/sources/k6/next/javascript-api/k6-data/sharedarray.md

@@ -54,7 +54,7 @@ However, certain operations can negate these benefits by converting the `SharedA
 
 ### Avoid array methods that create new arrays
 
-Methods like `.filter()` and `.map()` create new regular arrays when called on an already-created `SharedArray`, which removes the memory efficiency benefits.
+Methods like `.filter()` and `.map()` create regular arrays when called on a `SharedArray`, which removes the memory efficiency benefits.
 Instead, iterate over the `SharedArray` and process elements individually.
 
 However, you can use `.filter()` or `.map()` inside the `SharedArray` constructor function, since that operation only happens once during initialization.
@@ -119,7 +119,7 @@ export default function () {
 
 ### Avoid marshalling the entire SharedArray
 
-Marshalling or serializing a `SharedArray` (for example, with `JSON.stringify()`) converts it to a regular array representation, eliminating memory efficiency benefits.
+When you marshal or serialize a `SharedArray` (for example, with `JSON.stringify()`), it converts to a regular array representation, which eliminates memory efficiency benefits.
 Only marshal individual elements when needed.
 
 **Don't:**
@@ -184,7 +184,7 @@ export default function () {
 
 ### Avoid returning SharedArray from setup()
 
-Returning a `SharedArray` from the `setup()` function causes it to be marshalled, which removes its memory efficiency benefits.
+When you return a `SharedArray` from the `setup()` function, k6 marshals it, which removes its memory efficiency benefits.
 Keep `SharedArray` instances in the init context instead.
 
 **Don't:**