fix: wording

README.md

@@ -19,7 +19,7 @@ so there must be some misconceptions or inappropriate examples in the book.
 If anyone finds anything incorrect or have any questions / suggestions, just let me know about it by open an issue or join the discussion on [GitHub Discussions](https://github.com/ryan4yin/nixos-and-flakes-book/discussions), I'm glad continue to optimize the content of this book.
 
 The reason why I wrote this little book was only because no one in the community did it for me, who was a beginner at the time, so I chose to do it myself.
-Even though I knew I could make mistakes, it was much better than do nothing.
+Even though I knew I could make mistakes, it's much better than do nothing.
 
 My hope is that this book can help more people, enabling them to experience the joys of NixOS.
 Hope you like it!

docs/nixos-with-flakes/add-custom-cache-servers.md

@@ -229,7 +229,7 @@ In other words, you can use it like this:
 ## Accelerate Package Downloads via a Proxy Server {#accelerate-package-downloads-via-a-proxy-server} 
 
 > Referenced from Issue: [roaming laptop: network proxy configuration - NixOS/nixpkgs](https://github.com/NixOS/nixpkgs/issues/27535#issuecomment-1178444327)
-Although it was mentioned earlier that a transparent proxy running on your router or local machine can completely solve the issue of slow package downloads in NixOS, the configuration is rather cumbersome and often requires additional hardware.
+Although it's mentioned earlier that a transparent proxy running on your router or local machine can completely solve the issue of slow package downloads in NixOS, the configuration is rather cumbersome and often requires additional hardware.
 
 More users may prefer to directly speed up package downloads by using a HTTP/Socks5 proxy running on their machine. Here's how to set it up.
 Using methods like `export HTTPS_PROXY=http://127.0.0.1:7890` in the Terminal will not work because the actual work is done by a background process called `nix-daemon`, not by commands directly executed in the Terminal.

docs/preface.md

@@ -55,7 +55,7 @@ so there must be some misconceptions or complex cases in the book.
 If anyone finds anything incorrect or have any questions / suggestions, just let me know about it by opening an issue or joining the discussion on [GitHub Discussions](https://github.com/ryan4yin/nixos-and-flakes-book/discussions). I'm happy to continue improving the content of this book.
 
 The reason why I wrote this little book was only because no one in the community did it for me, who was a beginner at the time, so I chose to do it myself.
-Even though I knew I could make mistakes, it was much better than do nothing.
+Even though I knew I could make mistakes, it's much better than do nothing.
 
 My hope is that this book can help more people, enabling them to experience the joys of NixOS.
 Hope you like it!