* docs: add redux v.s. context difference FAQ entry

* PR review suggestions

* Capitalize React Context

Signed-off-by: An Xiao <hac@zju.edu.cn>

The original link was to a site that is no longer up. The book is
now hosted on a different site, so changed link to that.

`ChatActions` is not used in the commented file.

In this code example, SET_VISIBILITY_FILTER is used in a switch case, but it is never imported first. It is imported in the subsequent example code block in the docs. This is confusing, especially for users who aren't familiar with switch statements.

made license text point to the respective file

A couple of links in tables of contents were broken.

These were links where the URL fragment in the target was
auto-generated. When that happens, most special characters are removed
from the heading.

When the links in the tables of contents were written, the ones I am
fixing replaced some of the special characters with `-`, instead of
stripping them.

* Remove outdated rule on single quotes in docs

In PR #1874, a mass replacement of angled single quotes ’ with ASCII
single quotes ' was approved. Since then, the docs have contained a
mixture of angled and ASCII single quotes:

```
$ git log -S’ --since="Mon Aug 1 16:45:58 2016 -0400" --pretty=oneline |
wc -l
17
```

so it does not make sense to state a rule on them.

* Remove typographic stuff we don't use anyways.

I think this warning on using the Object spread operator to clone objects is important. While, good style would encourage the use of flat objects in the reducer, not everyone is going to do that. Using the spread syntax in a reducer on a multidimensional data structure is opening up the door to state mutation.

A slight improvement to the language, because:
1. "anymore" is not word
1. the second usage is also ambiguous - does it mean "we don't use it fromhereonin" or "we no longer use it"?

* Add type overload for combineReducers which strictly infers state shape and actions from the reducers object map.

* Fixed some typos.

* Please don't change version numbers in a PR

* Typescript 2.8 default type fixes.

…artial). (#3485)

* Preloaded state is now selectively partial (instead of deeply partial).

* Improved CombinedState, PreloadedState, and removed UnCombinedState.

Found a better way to type check CombinedState which allows the
$CombinedState symbol property marker to be optional. Since it's
optional, it's no longer necessary to strip it off in the Reducer state
parameter type and return type. This leaves the type definition for
Reducer unmodified, reduces the number of types required by one, and
makes the resolved types and stack traces clearer.

* Small change to the description of CombinedState.

* Removed DeepPartial import from tests.

Leaving the definition in place as removing it would be a breaking change.

* Made prettier happy.

* Made prettier happy with UsingObjectSpreadOperator.md

* Fixed combineReducers changeDetection logic(#3488)

* Cleaning up these and some other tests while I'm here


Co-authored-by: gupta <guptanub@amazon.com>
Co-authored-by: Tim Dorr <timdorr@users.noreply.github.com>