rustfmt: update configs for max 120-char line width

Author: valentinewallace

fuzz/rustfmt.toml

@@ -1,7 +1,7 @@
 # Non-default stable features
 hard_tabs = true # use tab characters for indentation, spaces for alignment
 use_field_init_shorthand = true
-max_width = 5000 # Initially set this to a big number to split the diff of the formatter into multiple commits.
+max_width = 120
 
 # Non-default unstable features
 unstable_features = true

rustfmt.toml

@@ -1,7 +1,7 @@
 # Non-default stable features
 hard_tabs = true # use tab characters for indentation, spaces for alignment
 use_field_init_shorthand = true
-max_width = 5000 # Initially set this to a big number to split the diff of the formatter into multiple commits.
+max_width = 120
 
 # Non-default unstable features
 unstable_features = true