README: added feature examples.

Author: azizk

README.md

@@ -6,6 +6,66 @@ ElixirSyntax was initially based on the [Elixir.tmbundle package](https://github
 
 See [CHANGELOG.md](./CHANGELOG.md) for the list of releases and noteworthy changes.
 
+## Features
+
+Some of the provided features are not immediately evident. Among them are:
+
+<style>
+  blockquote { font-family:monospace;white-space:pre;background-color:#282923;color:#eee !important }
+  .fnc { color:#67d8ef }
+  .blu_i { color:#67d8ef;font-style:italic }
+  .mod { color:#70a800 }
+  .kw { color:#f92472 }
+  .intp_bg { background-color: rgba(0, 0, 0, 0.03) }
+  .intp_dlm { color:#ababab }
+  .str_dlm { color:#dbca33 }
+  .str { color:#e7db74 }
+  .prpl { color:#ac80ff }
+  .akw { color:#8a66cc }
+  .colon { color:#aeafad }
+  .entity { color:#a6e22c }
+  .param { color:#fd9621;font-style:italic }
+</style>
+
+### The `fragment` and `sql` functions
+
+SQL syntax is highlighted inside Ecto's `fragment` macro.
+
+<blockquote><span class="mod">Post</span>
+<span class="kw">|></span> <span class="fnc">where</span>([post], <span class="fnc">fragment</span>(<span class="str_dlm">"</span><span class="prpl">?</span>.full_text <span class="kw">&lt;@</span> <span class="fnc">to_tsquery</span>(<span class="prpl">?</span>)<span class="str_dlm">"</span>, post, terms))
+</blockquote>
+
+Add an `sql` macro/function to your project to enjoy SQL highlighting anywhere it's used.
+
+<blockquote><span class="blu_i">defmacro</span> <span class="entity">sql</span>(<span class="param">sql</span>), <span class="akw">do</span><span class="colon">:</span> sql
+<span class="fnc">sql</span>(<span class="str_dlm">"</span><span class="kw">SELECT</span> <span class="param">*</span> <span class="kw">FROM</span> posts <span class="kw">ORDER</span> <span class="kw">BY</span> title <span class="kw">GROUP</span> <span class="kw">BY</span> user_id<span class="str_dlm">"</span>)
+</blockquote>
+
+### The JSON `~j` and `~J` sigils
+
+Embed JSON strings in your Elixir code. (Notice the interpolated Elixir code is rendered properly.)
+
+<blockquote><span class="blu_i">~j</span><span class="str_dlm">"""</span>
+{
+  <span class="str_dlm">"</span><span class="str">key</span><span class="str_dlm">"</span>: <span class="str_dlm">"</span><span class="intp_dlm">#{</span><span class="intp_bg">value</span><span class="intp_dlm">}</span><span class="str_dlm">"</span>,
+  <span class="str_dlm">"</span><span class="intp_dlm">#{</span><span class="intp_bg">key</span><span class="intp_dlm">}</span><span class="str_dlm">"</span>: <span class="str_dlm">"</span><span class="str">value</span><span class="str_dlm">"</span>
+}
+<span class="str_dlm">"""</span>
+</blockquote>
+
+### The YAML `~y` and `~Y` sigils
+
+<blockquote><span class="blu_i">~Y</span><span class="str_dlm">"""</span>
+<span class="kw">user</span>:
+  <span class="kw">name</span>: <span class="str">YAML</span>
+  <span class="kw">born</span>: <span class="prpl">2001</span><span class="prpl">-</span><span class="prpl">05</span><span class="prpl">-</span><span class="prpl">11</span>
+<span class="str_dlm">"""</span>
+</blockquote>
+
+### Etc.
+
+Also supported are LiveView (`~L"..."`) and the full PCRE syntax (`~r"..."`).
+
 ## Contributors/Maintainers
 
 - [@azizk](https://github.com/azizk) rewrote the whole syntax definition with an extensive test-suite and added a wealth of new features. ⭐