Fix spelling mistakes using codespell

This commit corrects various spelling mistakes throughout the
repository. The corrections were made automatically using `codespell`[1]
tool.

[1]: https://github.com/codespell-project/codespell

Change-Id: I1328f3ee46fdfd4b0285a235fe0dda51e36066e8
Signed-off-by: Manojkiran Eda <manojkiran.eda@gmail.com>
diff --git a/src/gpioplus/event.hpp b/src/gpioplus/event.hpp
index e36fdeb..5e378e9 100644
--- a/src/gpioplus/event.hpp
+++ b/src/gpioplus/event.hpp
@@ -77,7 +77,7 @@
     const internal::Fd& getFd() const;
 
     /** @brief Reads an event from the event file descriptor
-     *         Follows the read(2) semantics of the underyling file descriptor
+     *         Follows the read(2) semantics of the underlying file descriptor
      *
      *  @throws std::system_error for underlying syscall failures
      *  @return The value of the event or std::nullopt if the file descriptor