updated exception guarantees

README.md

@@ -104,11 +104,13 @@ where it improves legibility. Consult the source files for more information.
    - Modifiers
      - `Vec2 normalize()`
        - normalizes the vector and returns it
+       - throws when zero-vector
      - `Vec2 rotate(Vec2, value_t)`
        - rotates the vector and returns it
    - Supported Operators, All of these work as one would expect
      - `*` with `Vec2` (inner product) and `value_t`
-     - `/` with `value_t`, throws upon division by zero
+     - `/` with `value_t`
+       - throws upon division by zero
      - `+, -` with `Vec2`
      - All versions of `op=` of the above
      - `[]` with `std::size_t`