Minimize future false positive typos (#12751)

# Description

Make typos config more strict: ignore false positives where they occur.

1. Ignore only files with typos
2. Add regexp-s with context
3. Ignore variable names only in Rust code
4. Ignore only 1 "identifier"
5. Check dot files

🎁 Extra bonus: fix typos!!

crates/nu-command/src/date/utils.rs

@@ -8,7 +8,7 @@ pub(crate) fn parse_date_from_string(
     match dtparse::parse(input) {
         Ok((native_dt, fixed_offset)) => {
             let offset = match fixed_offset {
-                Some(fo) => fo,
+                Some(offset) => offset,
                 None => *(Local::now().offset()),
             };
             match offset.from_local_datetime(&native_dt) {