feat(solutions): add slugify/rust/function

challenges/slugify/solutions/rust/function/src/main.rs

@@ -0,0 +1,22 @@
+use std::io;
+
+fn main() {
+    let mut string = String::new();
+    io::stdin()
+        .read_line(&mut string)
+        .expect("Failed to read `stdin` line.");
+    let string = string.trim().trim_matches('-');
+    let mut answer = String::new();
+    let mut current = String::new();
+    for (_, character) in string.chars().enumerate() {
+        if character.is_whitespace() || (character == '-' && current.chars().count() > 0) {
+            answer.push_str(&current);
+            answer.push('-');
+            current.clear();
+        } else if character.is_alphanumeric() {
+            current.push(character);
+        }
+    }
+    answer.push_str(&current);
+    println!("{answer}");
+}