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-json/src/de.rs

@@ -260,8 +260,8 @@ where
                     }
                     _ => {
                         if chf == b'-' || chf.is_ascii_digit() {
-                            let mut pn = ParseNumber::new(self.str_buf.iter().copied());
-                            match pn.parse(false) {
+                            let mut parser = ParseNumber::new(self.str_buf.iter().copied());
+                            match parser.parse(false) {
                                 Ok(Number::F64(v)) => {
                                     self.rdr.uneat_char(ch);
                                     return visitor.visit_f64(v);