[DOCUMENTATION/BUG-FIX] Fix changelog for v0.5.0

[JVNpixels]

Fixes changelog for the 0.5.0 update!

• Adds Pico (Pico Mix) to the changelog
• Changes 10 Pico Remixes to 11 since Pico (Pico Mix) was forgotten. (Yes, I counted 5 times it is 11 songs)
• Fixed an extra space in Blammed (Pico Mix)
• Re-Explained how to unlock Darnell (BF Mix)
• Added the line where it says new animations have been added for Tankman and Pico

Does this PR close any issues? If so, link them below.

Briefly describe the issue(s) fixed.

Include any relevant screenshots or videos.

[JVNpixels]

The songs from Weekend 1 have moved; you must now switch to Pico via Character Select screen in Freeplay to access them This line I changed because the other lines said switch to pico through the character select screen while this one said freeplay, you can revert this one line only back if you want to :D