regex-debug: this removes regex-debug

There will be a new 'regex-cli' tool that will supplant this (and more).

Author: BurntSushi

Cargo.toml

@@ -18,7 +18,7 @@ edition = "2018"
 
 [workspace]
 members = [
-  "bench", "regex-capi", "regex-debug", "regex-syntax",
+  "bench", "regex-capi", "regex-syntax",
 ]
 
 [lib]