Change of Test instructions for 12.B

**Description**
Due to a modification in 12.B for software, the same change should be made in both Web and Docs. 

12.B Test Instructions should be: Check that all column and/or row headers are associated programmatically with all data cells. [SC 1.3.1]


**Which Baseline**
To help us address your issue more effectively, please identify which Baseline has the issue:
- Web
- Electronic Documents

