Error region is weird for redeclared variables

[MarcellPerger1]

Error region is weird for redeclared variables.
For example, it is

1 |  let foo = 9; let foo;
  |               ^^^^^^^

but should be:

1 |  let foo = 9; let foo;
  |                   ^^^  

Even worse, it is:

1 |  let foo = 9; let foo = 55;
  |               ^^^^^^^^^^^^  

but should be

1 |  let foo = 9; let foo = 55;
  |                   ^^^       

Because we should not highlight the entire expression when the error is just the identifier.