[Bug] Text box for back button on top navbar shows "Forward"

[Charlie-117]

Behavior of the program
The text box when mouse hovers on the back button on top navigation bar shows "Forward"

Expected behavior
The text box should show "Back" or "Backward"

To Reproduce
Steps to reproduce the behavior:

1. Open FreeTube
2. Hover mouse on back button on the top navigation bar
3. See error

Screenshots
https://imgur.com/a/odPfkTS

Environment Information (please complete the following information):

• OS: Linux Mint
• OS Version: 20.2
• FreeTube version: v0.14.0 Beta
• Installation Method (If applicable): .deb
• Primary API Used: Invidious API

Additional context

FreeTube/src/renderer/components/top-nav/top-nav.js

Line 64 in 818fa68

return this.$t('Backward')

The return value references a string (Backward) that doesn't exist, it should reference "Back" or the string will have to be renamed to "Backward".

FreeTube/static/locales/en-US.yaml

Line 29 in 818fa68

Back: Back