perf(dict): Avoid hashing unknwon words

Bypass hashing when we know (through str::len) that a word won't be in
the dict.

Master:
```
real    0m26.675s
user    0m33.683s
sys     0m4.535s
```

With this change:
```
real    0m24.060s
user    0m31.559s
sys     0m4.258s
```

crates/typos-dict/codegen/src/main.rs

@@ -13,6 +13,9 @@ fn generate<W: std::io::Write>(file: &mut W) {
     writeln!(file).unwrap();
     writeln!(file, "use unicase::UniCase;").unwrap();
 
+    let mut smallest = usize::MAX;
+    let mut largest = usize::MIN;
+
     writeln!(
         file,
         "pub static WORD_DICTIONARY: phf::Map<unicase::UniCase<&'static str>, &'static str> = "
@@ -26,12 +29,17 @@ fn generate<W: std::io::Write>(file: &mut W) {
         .map(|r| r.unwrap())
         .collect();
     for record in &records {
+        smallest = std::cmp::min(smallest, record[0].len());
+        largest = std::cmp::max(largest, record[0].len());
         let value = format!(r#""{}""#, &record[1]);
         builder.entry(unicase::UniCase::new(&record[0]), &value);
     }
     let codegenned = builder.build();
     writeln!(file, "{}", codegenned).unwrap();
     writeln!(file, ";").unwrap();
+    writeln!(file).unwrap();
+    writeln!(file, "pub const WORD_MIN: usize = {};", smallest).unwrap();
+    writeln!(file, "pub const WORD_MAX: usize = {};", largest).unwrap();
 }
 
 #[derive(Debug, StructOpt)]

crates/typos-dict/src/dict_codegen.rs

@@ -33648,3 +33648,6 @@ pub static WORD_DICTIONARY: phf::Map<unicase::UniCase<&'static str>, &'static st
         (UniCase::ascii("presumpton"), "presumption"),
     ]),
 };
+
+pub const WORD_MIN: usize = 3;
+pub const WORD_MAX: usize = 19;

src/dict.rs

@@ -44,7 +44,13 @@ impl BuiltIn {
 
     // Not using `Status` to avoid the allocations
     fn correct_with_dict(&self, word: &str) -> Option<&'static str> {
-        map_lookup(&typos_dict::WORD_DICTIONARY, word)
+        const WORD_RANGE: std::ops::RangeInclusive<usize> =
+            typos_dict::WORD_MIN..=typos_dict::WORD_MAX;
+        if WORD_RANGE.contains(&word.len()) {
+            map_lookup(&typos_dict::WORD_DICTIONARY, word)
+        } else {
+            None
+        }
     }
 
     fn correct_with_vars(&self, word: &str) -> Option<Status<'static>> {