Finder stopped showing the content of a text file
To show contents of a text file you must have the correct settings for your Finder window. You can't use icon view or list view. Your figure shows you are using list view. That view has never shown file contents on my computer. On the Finder header bar there is a label that reads "View", and above that are four icon options: the first is icon view and the second is list view. You want the third option but I don't know what its called. If you select this way of viewing the contents of the Finder window, text files and other types are displayed showing the 1st page of the contents of a file. The correct viewing option is shown in the figure below.