Search and replace seemed to work, but didn’t

I am probably making some kind of rookie mistake but would appreciate anyone who could help me out.
my client put a large number of files in a folder called “pdfs” in the wp-includes folder and linked to them through-out the site.
To fix I move them to a folder called “media” rather than inside wp-includes.

I ran Better Search and Replace searching for “thedomain.ca/wp-includes/pdfs” and replacing it with “thedomain.ca/media/pdfs”

I highlighted all tabled clicked on run, and it did it’s thing. Told me it had made changes in several places. All good.
Went to site clicked on a link and it went to the old location…
I’m definitely doing something wrong, but can’t figure it out.
Do I need to use a different plugin or approach to change all the links in the site pages? Or…?
Thanks in advance for your help,
ernie