Javascript programming every day of the week

I use Safari for testing websites and for cruising Facebook, but it's been paining me that the tab-switching uses different keys than every other browser. Today, after absent-mindedly once again failing to move from the tab I was on, I searched for a way to customize the shortcuts. There's nothing specific to Safari, but... There is a Mac-wide way to set keyboard shortcuts, which can be made specific to Safari. And despite not restarting Safari after setting it up, I just absent-mindedly switched tabs and it worked! These are the instructions I followed. This is what I wrote in Step 4, just in case you need to make this change in your own life:

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(I was just so pleased that it worked. The dearth of Google results wasn't filling me with confidence.)