docs(readme): improve text and markup; rm badge

README.md

@@ -1,39 +1,35 @@
 # s2png — “stuff to PNG”
 
-[![GitHub Actions CI status.](https://github.com/dbohdan/s2png/actions/workflows/ci.yml/badge.svg)](https://gthub.com/dbohdan/s2png/actions/workflows/ci.yml)
-
-This program encodes arbitrary binary data in PNG images that look like noise
-and decodes it back. It was originally developed by k0wax
-[on SourceForge](http://sourceforge.net/projects/s2png/). I started this fork
-to fix a problem that caused s2png 0.01 to segfault when compiled on a modern
-operating system. The fork has since accumulated various bug fixes and
-improvements. Most recently, I have ported it to Rust. Among other things,
-this makes it easier to distribute s2png as a static binary. The fork remains
-data-compatible with the original if you don't use the toy encryption feature.
+This program converts arbitrary binary data to and from PNG images that look like noise.
+It was originally developed by k0wax
+[on SourceForge](http://sourceforge.net/projects/s2png/).
+I started this fork to fix a problem that caused s2png 0.01 to segfault
+when compiled on a 2010s operating system.
+The fork has since accumulated various bug fixes and improvements.
+Most recently, I have ported it from C to Rust.
+Among other things, this makes it easier to distribute s2png as a static binary.
+The fork remains data-compatible with the original
+if you don't use the toy encryption feature.
 
 
 ## Installation
 
-Prebuilt binaries are available for x86\_64 Linux and i686 Windows. They are
-attached to releases on the
-[Releases](https://github.com/dbohdan/s2png/releases) page. Development
-(unstable) binaries are also
-[automatically built](https://ci.appveyor.com/project/dbohdan/s2png/build/artifacts)
-for Windows.
+Prebuilt binaries are available for x86-64 Linux and i686 Windows.
+They are attached to releases on the
+["Releases"](https://github.com/dbohdan/s2png/releases) page.
 
 ### Installing with Cargo
 
-```shell
+```sh
 cargo install s2png
 ```
 
 ### Building on Debian and Ubuntu
 
-Follow the instructions to build a static Linux binary of s2png from source
-on recent Debian and Ubuntu.
+Follow the instructions to build a static Linux binary of s2png from the source code on recent Debian and Ubuntu.
 
-1\. Install [Rustup](https://rustup.rs/). Through Rustup, add the stable musl
-libc target for your CPU.
+1\. Install [Rustup](https://rustup.rs/).
+    Through Rustup, add the stable musl libc target for your CPU.
 
 ```sh
 rustup target add x86_64-unknown-linux-musl
@@ -46,20 +42,22 @@ sudo apt install build-essential musl-tools
 cargo install just
 ```
 
-3\. Clone this repository. Build the binary.
+3\. Clone this repository.
+    Build the binary.
 
-    git clone https://github.com/dbohdan/s2png
-    cd s2png
-    just test
-    just release-linux
+```sh
+git clone https://github.com/dbohdan/s2png
+cd s2png
+just test
+just release-linux
+```
 
 ### Cross-compiling for Windows
 
-Follow the instructions to build a 32-bit Intel Windows binary of s2png on
-recent Debian and Ubuntu.
+Follow the instructions to build a 32-bit Intel Windows binary of s2png on recent Debian and Ubuntu.
 
-1\. Install [Rustup](https://rustup.rs/). Through Rustup add the i686 GNU ABI
-Windows target.
+1\. Install [Rustup](https://rustup.rs/).
+    Through Rustup, add the i686 GNU ABI Windows target.
 
 ```sh
 rustup target add i686-pc-windows-gnu
@@ -72,20 +70,22 @@ sudo apt install build-essential mingw-w64
 cargo install just
 ```
 
-3\. Configure Cargo for cross-compilation. Add the following in
-`~/.cargo/config`.
+3\. Configure Cargo for cross-compilation.
+  Add the following in `~/.cargo/config`.
 
 ```toml
 [target.i686-pc-windows-gnu]
 linker = "/usr/bin/i686-w64-mingw32-gcc"
 ```
 
-4\. Clone this repository. Build the binary.
-
-    git clone https://github.com/dbohdan/s2png
-    cd s2png
-    just release-windows
+4\. Clone this repository.
+    Build the binary.
 
+```sh
+git clone https://github.com/dbohdan/s2png
+cd s2png
+just release-windows
+```
 
 ## Usage
 
@@ -117,31 +117,39 @@ See README.md for further details.
 
 ## Examples
 
-To store `foo.mp3` in an image enter the following command:
+To store `foo.mp3` in an image, enter the following command:
 
-    s2png foo.mp3
+```sh
+s2png foo.mp3
+```
 
 A file named `foo.mp3.png` will be created in the same directory as `foo.mp3`.
 
-Add the `-s` switch to ensure the resulting image is square (give or take a
-pixel) and `-b "some text"` to change the text of the banner at the bottom.
+Add the `-s` switch to make the resulting image square (give or take a pixel)
+and `-b "some text"` to change the text of the banner at the bottom.
 
-    s2png -s -b hello foo.mp3
+```sh
+s2png -s -b hello foo.mp3
+```
 
-To decode `decode_me.mp3.png` and retrieve the original file `decode_me.mp3` run
-the command
+To decode `decode_me.mp3.png` and retrieve the original file `decode_me.mp3`,
+run the command
 
-    s2png decode_me.mp3.png
+```sh
+s2png decode_me.mp3.png
+```
 
 Decode `xyz.png` to `decoded.mp3` with
 
-    s2png -o decoded.mp3 xyz.png
-
+```sh
+s2png -o decoded.mp3 xyz.png
+```
 
 ## License
 
-s2png is licensed under the GNU GPL 2.0. See the file `LICENSE`. The
-implementation of the RC4 streaming cypher in [`src/rc4/mod.rs`](src/rc4/mod.rs)
-is in the public domain. The font from [libgd](https://github.com/libgd/libgd)
-is distributed under its BSD-like license. See the file
-[`src/font/COPYING.libgd`](src/font/COPYING.libgd).
+s2png is distributed under the GNU GPL 2.0.
+See the file [`LICENSE`](LICENSE).
+The implementation of the RC4 streaming cypher in [`src/rc4/mod.rs`](src/rc4/mod.rs)
+is in the public domain.
+The font from [libgd](https://github.com/libgd/libgd) is distributed under its BSD-like license.
+See the file [`src/font/COPYING.libgd`](src/font/COPYING.libgd).