api-docs: Extract installation instructions to their own section.

templates/zerver/api/installation-instructions.md

@@ -1,16 +1,55 @@
 # Installation instructions
 
-#### Python Installation
+Zulip's REST API is easy to work with directly, but there are API
-Install it with [pip](https://pypi.python.org/pypi/zulip/):
+libraries available for various popular languages.
+
+The Python library is the most advanced (and has tools for easily
+writing interactive bots that react to messages), so we recommend it
+if you're trying to decide.
+
+<div class="code-section" markdown="1">
+<ul class="nav">
+<li data-language="curl">curl</li>
+<li data-language="python">Python</li>
+<li data-language="zulip-send">zulip-send</li>
+<li data-language="javascript">JavaScript</li>
+</ul>
+<div class="blocks">
+
+<div data-language="curl" markdown="1">
+No download required!
+</div>
+
+<div data-language="zulip-send" markdown="1">
+Included with the Python bindings:
+
 ```
 pip install zulip
 ```
-#### JavaScript Installation
+
-Install it with [npm](https://www.npmjs.com/package/zulip-js):
+</div>
+
+<div data-language="python" markdown="1">
+Install the Python API with [pip](https://pypi.python.org/pypi/zulip/):
+
+```
+pip install zulip
+```
+
+</div>
+
+<div data-language="javascript" markdown="1">
+Install the JavaScript API with [npm](https://www.npmjs.com/package/zulip-js):
+
 ```
 npm install zulip-js
 ```
 
+</div>
+
+</div>
+</div>
+
 ### Usage examples
 <div class="code-section" markdown="1">
 <ul class="nav">
@@ -22,8 +61,6 @@ npm install zulip-js
 <div class="blocks">
 
 <div data-language="curl" markdown="1">
-No download required!
-
 #### Stream message
 
 ```