normalize special characters in module names to allow variable access (#14353)

Fixes #14252

# User-Facing Changes

- Special characters in module names are replaced with underscores when
  importing constants, preventing "expected valid variable name":

```nushell
> module foo-bar { export const baz = 1 }
> use foo-bar
> $foo_bar.baz
```

- "expected valid variable name" errors now include a suggestion list:

```nushell
> module foo-bar { export const baz = 1 }
> use foo-bar
> $foo-bar
Error: nu::parser::parse_mismatch_with_did_you_mean

  × Parse mismatch during operation.
   ╭─[entry #1:1:1]
 1 │ $foo-bar;
   · ────┬───
   ·     ╰── expected valid variable name. Did you mean '$foo_bar'?
   ╰────
```

crates/nu-protocol/src/errors/parse_error.rs

@@ -55,6 +55,10 @@ pub enum ParseError {
     #[diagnostic(code(nu::parser::parse_mismatch_with_full_string_msg))]
     ExpectedWithStringMsg(String, #[label("expected {0}")] Span),
 
+    #[error("Parse mismatch during operation.")]
+    #[diagnostic(code(nu::parser::parse_mismatch_with_did_you_mean))]
+    ExpectedWithDidYouMean(&'static str, DidYouMean, #[label("expected {0}. {1}")] Span),
+
     #[error("Command does not support {0} input.")]
     #[diagnostic(code(nu::parser::input_type_mismatch))]
     InputMismatch(Type, #[label("command doesn't support {0} input")] Span),
@@ -551,6 +555,7 @@ impl ParseError {
             ParseError::Unbalanced(_, _, s) => *s,
             ParseError::Expected(_, s) => *s,
             ParseError::ExpectedWithStringMsg(_, s) => *s,
+            ParseError::ExpectedWithDidYouMean(_, _, s) => *s,
             ParseError::Mismatch(_, _, s) => *s,
             ParseError::UnsupportedOperationLHS(_, _, s, _) => *s,
             ParseError::UnsupportedOperationRHS(_, _, _, _, s, _) => *s,