docs: change wording in docs (#11933)

docs/guide/why.md

@@ -33,7 +33,7 @@ import esmSvg from '../images/esm.svg?raw'
 
 ### Slow Updates
 
-When a file is edited in a bundler-based build setup, it is inefficient to rebuild the whole bundle for obvious reasons: the update speed will degrade linearly with the size of the app.
+When a file is edited in a bundler-based build setup, it is inefficient to rebuild the whole bundle for an obvious reason: the update speed will degrade linearly with the size of the app.
 
 In some bundlers, the dev server runs the bundling in memory so that it only needs to invalidate part of its module graph when a file changes, but it still needs to re-construct the entire bundle and reload the web page. Reconstructing the bundle can be expensive, and reloading the page blows away the current state of the application. This is why some bundlers support Hot Module Replacement (HMR): allowing a module to "hot replace" itself without affecting the rest of the page. This greatly improves DX - however, in practice we've found that even HMR update speed deteriorates significantly as the size of the application grows.