feat(solutions): add acronyms/rust/function

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

@@ -0,0 +1,21 @@
+use std::io;
+
+pub fn get_acronym(sentence: &str) -> String {
+    let words = sentence.replace("\"", "");
+    let words = words.split_whitespace();
+    let mut acronym = String::new();
+    for word in words {
+        if let Some(character) = word.to_uppercase().chars().next() {
+            acronym.push(character);
+        }
+    }
+    acronym
+}
+
+fn main() {
+    let mut input = String::new();
+    io::stdin()
+        .read_line(&mut input)
+        .expect("Failed to read `stdin` line.");
+    println!("{}", get_acronym(&input));
+}