Fixed some typos

Just for a specific reddit user jaja. Also did some minor changes with how the string parsing is done.

README.md

@@ -22,7 +22,7 @@ torrent based projects.
 magnet_url has the goal of, as you may have guessed, parsing the parts of magnets. It does
 this using some relatively simple regexes. The crate is designed to be very simple and efficient,
 with a lot of flexibility. It's also designed to be relatively easy to handle errors, and
-modification of it's source is greatly encouraged through documentation and it's license.
+modification of its source is greatly encouraged through documentation and its license.
 
 ## How to use this crate
 Parsing a magnet is very simple:

src/lib.rs

@@ -38,7 +38,7 @@ const MANIFEST_TOPIC_RE_STR: &str = r"mt=((\w+)[A-Za-z0-9!@#$%^:*<>,?/()_+=.{}\\
 /// magnet_url has the goal of, as you may have guessed, parsing the parts of magnets. It does
 /// this using some relatively simple regexes. The crate is designed to be very simple and efficient,
 /// with a lot of flexibility. It's also designed to be relatively easy to handle errors, and
-/// modification of it's source is greatly encouraged through documentation and it's license.
+/// modification of its source is greatly encouraged through documentation and its license.
 ///
 /// ## How to use this crate
 /// Parsing a magnet is very simple:
@@ -160,7 +160,7 @@ impl Magnet {
 
         let validate_regex = |regex: &Regex, re_group_index| -> String {
             match regex.captures(magnet_str) {
-                Some(m) => m.get(re_group_index).map_or("", |m| m.as_str()).to_string(),
+                Some(m) => m.get(re_group_index).map_or(String::new(), |m| m.as_str().to_string()),
                 None => String::new()
             }
 
@@ -173,7 +173,7 @@ impl Magnet {
             // Using a slightly modified match statement so it doesn't parse from str to String to int
             xl: {
                 match &EXACT_LENGTH_RE.captures(magnet_str) {
-                    Some(m) => m.get(1).map_or("-1", |m| m.as_str()).parse().unwrap_or(-1),
+                    Some(m) => m.get(1).map_or(-1, |m| m.as_str().parse().unwrap()),
                     None => -1,
                 }
 
@@ -183,7 +183,7 @@ impl Magnet {
                 let mut tr_vec: Vec<String> = Vec::new();
                 // Since tr is a vector, I can't just use the validate_regex function
                 for tr in ADDRESS_TRACKER_RE.captures_iter(magnet_str) {
-                    tr_vec.push(tr.get(1).map_or("", |m| m.as_str()).to_string());
+                    tr_vec.push(tr.get(1).map_or(String::new(), |m| m.as_str().to_string()));
                 }
 
                 tr_vec