Format let-else expressions

[jedel1043]

This PR runs cargo +nightly fmt to format all our let-else expressions with the newest rustfmt binary, which now supports let-else.

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	94,842	94,842	0
Passed	74,691	74,691	0
Ignored	18,812	18,812	0
Failed	1,339	1,339	0
Panics	0	0	0
Conformance	78.75%	78.75%	0.00%

[codecov]

Codecov Report

Merging #3102 (f2ba9ec) into main (9b1f2f4) will increase coverage by 0.23%.
The diff coverage is 32.55%.

@@            Coverage Diff             @@
##             main    #3102      +/-   ##
==========================================
+ Coverage   50.42%   50.65%   +0.23%     
==========================================
  Files         444      444              
  Lines       45877    42648    -3229     
==========================================
- Hits        23132    21605    -1527     
+ Misses      22745    21043    -1702     

Impacted Files	Coverage Δ
boa_cli/src/debug/function.rs	0.00% <0.00%> (ø)
boa_cli/src/debug/limits.rs	0.00% <0.00%> (ø)
boa_cli/src/debug/object.rs	0.00% <0.00%> (ø)
boa_cli/src/debug/shape.rs	0.00% <0.00%> (ø)
boa_engine/src/builtins/escape/mod.rs	12.82% <0.00%> (ø)
boa_engine/src/builtins/generator/mod.rs	36.49% <0.00%> (+4.64%)	⬆️
boa_engine/src/builtins/intl/list_format/mod.rs	5.66% <0.00%> (+0.68%)	⬆️
boa_engine/src/builtins/intl/segmenter/iterator.rs	15.51% <0.00%> (+1.23%)	⬆️
boa_engine/src/builtins/intl/segmenter/segments.rs	18.18% <0.00%> (+3.08%)	⬆️
boa_engine/src/class.rs	0.00% <0.00%> (ø)
... and 16 more

... and 171 files with indirect coverage changes