strands tut: minor. introduce next code example.

Author: nbogie

src/content/tutorials/en/intro-to-p5-strands.mdx

@@ -624,7 +624,9 @@ For step 2, perhaps it is helpful to _imagine_ the following code being run each
 ```js
 bloomShader.setUniform("ogImage", getOriginalImage())
 ```
-(You shouldn't write the above code - something like it is written and run for you, behind the scenes).
+(You shouldn't _write_ the above code - something like it is written and run for you, behind the scenes).
+
+Here's our `bloomCallback` function with this original canvas image being received by the shader and sampled from:
 
 ```js
 function getOriginalImage(){