grep-regex: fix inner literal extraction bug

This appears to be another transcription bug from copying this code from
the prefix literal detection from inside the regex crate. Namely, when
it comes to inner literals, we only want to treat counted repetition as
two separate cases: the case when the minimum match is 0 and the case
when the minimum match is more than 0. In the former case, we treat
`e{0,n}` as `e*` and in the latter we treat `e{m,n}` where `m >= 1` as
just `e`.

We could definitely do better here. e.g., This means regexes like
`(foo){10}` will only have `foo` extracted as a literal, where searching
for the full literal would likely be faster.

The actual bug here was that we were not implementing this logic
correctly. Namely, we weren't always "cutting" the literals in the
second case to prevent them from being expanded.

Fixes #1319, Closes #1367

tests/regression.rs

@@ -729,6 +729,14 @@ rgtest!(r1259_drop_last_byte_nonl, |dir: Dir, mut cmd: TestCommand| {
     eqnice!("fz\n", cmd.arg("-f").arg("patterns-nl").arg("test").stdout());
 });
 
+// See: https://github.com/BurntSushi/ripgrep/issues/1319
+rgtest!(r1319, |dir: Dir, mut cmd: TestCommand| {
+    dir.create("input", "CCAGCTACTCGGGAGGCTGAGGCTGGAGGATCGCTTGAGTCCAGGAGTTC");
+    eqnice!(
+        "input:CCAGCTACTCGGGAGGCTGAGGCTGGAGGATCGCTTGAGTCCAGGAGTTC\n",
+        cmd.arg("TTGAGTCCAGGAG[ATCG]{2}C").stdout());
+});
+
 // See: https://github.com/BurntSushi/ripgrep/issues/1334
 rgtest!(r1334_crazy_literals, |dir: Dir, mut cmd: TestCommand| {
     dir.create("patterns", &"1.208.0.0/12\n".repeat(40));