Reformat all files

This runs build_tools/style.fish, which runs clang-format on C++, fish_indent on fish and (new) black on python.

If anything is wrong with the formatting, we should fix the tools, but automated formatting is worth it.

share/functions/__fish_anypython.fish

@@ -1,6 +1,6 @@
 function __fish_anypython
     # Try python3 first, because that's usually faster and generally nicer.
-	for py in python3 python2 python
+    for py in python3 python2 python
         command -sq $py
         and echo $py
         and return 0