Use gender-neutral language in comments

examples/cocoa/CocoaAppDelegate.mm

@@ -120,7 +120,7 @@ struct SFMLmainWindow
          * periodically we need to add it to the two above runloop mode.
          *
          * The default mode allows timer firing while the user doesn't do anything
-         * while the second mode allows timer firing while he is using a slider
+         * while the second mode allows timer firing while they are using a slider
          * or a menu.
          */
 

examples/voip/Client.cpp

@@ -107,7 +107,7 @@ private:
 
 ////////////////////////////////////////////////////////////
 /// Create a client, connect it to a running server and
-/// start sending him audio data
+/// start sending it audio data
 ///
 ////////////////////////////////////////////////////////////
 void doClient(unsigned short port)

include/SFML/Network/SocketSelector.hpp

@@ -237,7 +237,7 @@ private:
 ///             if (listener.accept(client) == sf::Socket::Status::Done)
 ///             {
 ///                 // Add the new client to the selector so that we will
-///                 // be notified when he sends something
+///                 // be notified when they send something
 ///                 selector.add(client);
 ///
 ///                 // Add the new client to the clients list

src/SFML/Window/iOS/SFMain.mm

@@ -30,20 +30,20 @@
 
 // sfmlMain is called by the application delegate (SFAppDelegate).
 //
-// Since we don't know which prototype of main the user
-// defines, we declare both versions of sfmlMain, but with
-// the 'weak' attribute (GCC extension) so that the
+// Since we don't know which prototype of `main` the user
+// defines, we declare both versions of `sfmlMain`, but with
+// the `weak` attribute (GCC extension) so that the
 // user-declared one will replace SFML's one at linking stage.
 //
-// If user defines main(argc, argv) then it will be called
-// directly, if he defines main() then it will be called by
+// If the user defines `main(argc, argv)` then it will be called
+// directly, if they define `main()` then it will be called by
 // our placeholder.
 //
-// The sfmlMain() version is never called, it is just defined
+// The `sfmlMain()` version is never called, it is just defined
 // to avoid a linker error if the user directly defines the
 // version with arguments.
 //
-// See the sfml-main module for the other half of this
+// See the `sfml-main` module for the other half of this
 // initialization trick.