feat: add comment support to saccharine language

Add '#' comment syntax that works like Python comments.
Comments can take up a whole line or appear at the end of a line.
All characters after '#' until the next newline or EOF are ignored.

Closes #24

pkg/saccharine/token/parse.go

@@ -77,6 +77,23 @@ func getToken(i *iterator.Iterator[rune]) (*Token, error) {
 		}
 	case letter == ';':
 		return NewHardBreak(index), nil
+	case letter == '#':
+		// Skip everything until the next newline or EOF
+		for {
+			if i.Done() {
+				break
+			}
+			r, err := i.Next()
+			if err != nil {
+				return nil, trace.Wrap(err, "error while parsing comment")
+			}
+			if r == '\n' {
+				// Put the newline back so it can be processed as a soft break
+				i.Back()
+				break
+			}
+		}
+		return nil, nil
 	case unicode.IsSpace(letter):
 		return nil, nil
 	case isVariable(letter):