docs: make mention of modules section & run rustfmt

ladderz/src/lib.rs

@@ -2,6 +2,8 @@
 //!
 //! Implementations of mathematical and technical concepts in Rust.
 //!
+//! View [the modules section](#modules) for the various implementations based on the subject.
+//!
 //! # Example
 //!
 //! Here's an example of using the `ladderz` crate to get the factors and factor pairs of a number in sorted order.

ladderz/src/pre_algebra/unit1.rs

@@ -223,7 +223,7 @@ pub fn is_multiple(x: u32, y: u32) -> bool {
 pub fn get_multiples_in_range(n: u32, end: u32) -> HashSet<u32> {
     let mut multiples: HashSet<u32> = HashSet::new();
 
-    for num in n..end+1 {
+    for num in n..end + 1 {
         if num % n == 0 {
             multiples.insert(num);
         }