docs: Build out HACS installation instructions

This commit primarily builds out the HACS instructions on the
installation doc page so that a new user who may not be familiar
with HACS or have it installed will have enough background to
get pyscript installed. Along with this, it synchronizes instructions
regarding what to click with the button labels in Home Assistant
(e.g., "Configuration ->" becomes "Settings -> Devices & services ->").

Secondary changes made address a few typographical issues in
several documents. Only one change was made to a code snippet
in 'tutorial.rst', relabeling 'pararm2' to 'param2'.

Note: At the end of 'tutorial.rst' there was a transition paragraph
intended to introduce another section that would describe
decorators/built-ins. This section was missing from the
page, so I removed the transition paragraph. However, it could be
added back when that section is finished.

Author: amckenny

docs/installation.rst

@@ -1,11 +1,25 @@
 Installation
 ============
 
-Option 1: HACS
+Option 1: Home Assistant Community Store (HACS)
 --------------
 
-Under HACS -> Integrations, select “+”, search for ``pyscript`` and
-install it.
+HACS is an integration in Home Assistant that allows you to
+install custom integrations, frontend elements, and add-ons
+developed by the Home Assistant community without the need
+to manually download and copy files. To install HACS, follow
+the instructions on the
+`HACS website <https://hacs.xyz/docs/setup/prerequisites/>`__.
+
+With HACS installed, under HACS -> Integrations, select “+”,
+search for ``pyscript``, and install it.
+
+During installation you will be asked to identify whether to
+allow all imports and whether to allow access to HASS as a
+global variable. These settings are documented on the
+`overview <https://github.com/custom-components/pyscript/blob/master/docs/overview.rst>`__
+page and can be changed after installation in the integration
+configuration.
 
 Option 2: Manual
 ----------------

docs/overview.rst

@@ -8,28 +8,28 @@ callable as Python functions, so it's easy and concise to implement
 logic.
 
 Functions you write can be configured to be called as a service or run
-upon time, state-change or event triggers. Functions can also call any
-service, fire events and set state variables. Functions can sleep or
+upon time, state-change, or event triggers. Functions can also call any
+service, fire events, and set state variables. Functions can sleep or
 wait for additional changes in state variables or events, without
 slowing or affecting other operations. You can think of these functions
 as small programs that run in parallel, independently of each other, and
 they could be active for extended periods of time.
 
-State, event and time triggers are specified by Python function
+State, event, and time triggers are specified by Python function
 decorators (the "@" lines immediately before each function definition).
 A state trigger can be any Python expression using state variables - the
 trigger is evaluated only when a state variable it references changes,
 and the trigger occurs when the expression is true or non-zero. A time
-trigger could be a single event (eg: date and time), a repetitive event
-(eg: at a particular time each day or weekday, daily relative to sunrise
-or sunset or any regular time period within an optional range) or using
+trigger could be a single event (e.g., date and time), a repetitive event
+(e.g., at a particular time each day or weekday, daily relative to sunrise
+or sunset, or any regular time period within an optional range), or using
 cron syntax (where events occur periodically based on a concise
-specification of ranges of minutes, hours, days of week, days of month
+specification of ranges of minutes, hours, days of week, days of month,
 and months). An event trigger specifies the event type, and an optional
 Python trigger test based on the event data that runs the Python
 function if true.
 
-Pyscript implements a Python interpreter using the ast parser output, in
+Pyscript implements a Python interpreter using the AST parser output, in
 a fully async manner. That allows several of the "magic" features to be
 implemented in a seamless Pythonic manner, such as binding of variables
 to states and functions to services. Pyscript supports imports, although
@@ -41,10 +41,10 @@ generators, ``yield``, and defining special class methods.
 Pyscript provides a handful of additional built-in functions that connect
 to HASS features, like logging, accessing state variables as strings
 (if you need to compute their names dynamically), running and managing
-tasks, sleeping and waiting for triggers.
+tasks, sleeping, and waiting for triggers.
 
 Pyscript also provides a kernel that interfaces with the Jupyter
-front-ends (eg, notebook, console, lab and VSC). That allows you to develop
+front-ends (eg, notebook, console, lab, and VSC). That allows you to develop
 and test pyscript code interactively. Plus you can interact with much of
 HASS by looking at state variables, calling services etc, in a similar
 way to `HASS
@@ -59,11 +59,11 @@ which can be downloaded and run interactively in Jupyter notebook or VSC
 connected to your live HASS with pyscript.
 
 Pyscript provides functionality that complements the existing
-automations, templates and triggers. Pyscript is most similar to
+automations, templates, and triggers. Pyscript is most similar to
 `AppDaemon <https://appdaemon.readthedocs.io/en/latest/>`__, and some
 similarities and differences are discussed in this `Wiki
 page <https://github.com/custom-components/pyscript/wiki/Comparing-Pyscript-to-AppDaemon>`__.
-Pyscript with Jupyter makes it extremely easy to learn, use and debug.
+Pyscript with Jupyter makes it extremely easy to learn, use, and debug.
 Pyscripts presents a simplified and more integrated binding for Python
 scripting than `Python
 Scripts <https://www.home-assistant.io/integrations/python_script>`__,