Fix typos

Found via `typos --hidden --format brief`

Author: kianmeng

README.md

@@ -61,7 +61,7 @@ and [Argon2id](https://en.wikipedia.org/wiki/Argon2) for key derivation.
 It also uses [AES-GCM](https://docs.rs/aes-gcm/latest/aes_gcm/) to import from encrypted Aegis backups.
 
 
-## Cross Plaform
+## Cross Platform
 
 cotp should be easily compiled on the most used platforms, but it is mostly tested on Linux, Windows and macOS.
 

src/interface/handlers/main_window.rs

@@ -126,7 +126,7 @@ fn handle_counter_switch(app: &mut App, increment: bool) {
     if let Some(selected) = app.table.state.selected() {
         if let Some(element) = app.database.mut_element(selected) {
             if element.type_ == OTPType::Hotp {
-                // safe to unwrap becouse the element type is HOTP
+                // safe to unwrap because the element type is HOTP
                 let counter = element.counter.unwrap();
                 element.counter = if increment {
                     Some(counter.checked_add(1).unwrap_or(u64::MAX))

src/otp/algorithms/yandex_otp_maker.rs

@@ -21,7 +21,7 @@ use crate::otp::otp_error::OtpError;
 use super::hotp_maker::hotp_hash;
 
 const EN_ALPHABET_LENGTH: u64 = 26;
-const SECRET_LENGHT: usize = 16;
+const SECRET_LENGTH: usize = 16;
 
 pub fn yandex(
     secret: &str,
@@ -70,13 +70,13 @@ where
         Err(e) => return Err(OtpError::SecretEncoding(e.kind, e.position)),
     };
 
-    if decoded_secret.len() < SECRET_LENGHT {
+    if decoded_secret.len() < SECRET_LENGTH {
         return Err(OtpError::ShortSecret);
     }
 
-    let parsed_secret = &decoded_secret.as_slice()[0..SECRET_LENGHT];
+    let parsed_secret = &decoded_secret.as_slice()[0..SECRET_LENGTH];
 
-    let mut pin_with_secret: Vec<u8> = Vec::with_capacity(pin.len() + SECRET_LENGHT);
+    let mut pin_with_secret: Vec<u8> = Vec::with_capacity(pin.len() + SECRET_LENGTH);
 
     pin_with_secret.append(&mut pin.as_bytes().to_vec());
     pin_with_secret.append(&mut parsed_secret.to_vec());