I've got a game that doesn't autoreload ReShade Framework when I make a change to one of the shader files. Is there a key that forces ReShade to reload?

No. It will always reload on changes to a shader file. Some text editors don't actually change the file directly on save though, but create a new temporary file, write the data to it and then replace the old file with the new file. ReShade does not catch that. So try to force a reload by opening the file in Windows Notepad and just hit the save button there.