RIMOV, round 5

find ./ -type f -name "*.rs" -exec sed -i "s/\&\[mut /\&mut \[/g" {} \;
Remove two FIXMEs from the long-dead issue 3226
RIMOV, round 6.

This gets rid of `mut` inside bare vectors. It's going to cause some
problems later.
RIMOV, round 7

find ./ -type f -name "*.rs" -exec sed -i "s/ mut \([a-zA-Z_]\+\):
~\[mut / mut \1: ~\[/g" {} \;
RIMOV, round 8

find ./ -type f -name "*.rs" -exec sed -i "s/  \([a-zA-Z_]\+\): ~\[mut /
mut \1: ~\[/g" {} \;
RIMOV, round 10

find ./ -type f -name "*.rs" -exec sed -i "s/~\[mut /~\[/g" {} \;
RIMOV, round 11

Last bit of mut removal, manually cleaning up outliers
What, no syntax for mutable borrowed region pointers?
Revert RIMOV for libcore
Repair RIMOV damage to libstd
Fix RIMOV damage to libsyntax
Revert RIMOV on librustc
Repair RIMOV damage to libstd tests
Repair RIMOV damage to run-pass
RIMOV: fix issue-3563-3 test
Revert RIMOV to compile-fail tests
Repair RIMOV damage to benchmarks
Fix bench/sudoku, broken by deëxporting
Repair RIMOV damage to doc tests
test: De-export sudoku. rs=burningtree