Do not warn find --help (fixes #1188)

End column

Check popd flags for -n (fixes #1252)

Remove unnecessary dot

The dot after the screenshot is strange so this commit remove it.

This does the necessary work to emit end columns on AST analyses. SC2086
is made to emit a correct end column as an illustrative example.

For example:
```
$ shellcheck -s bash -f json /dev/stdin <<< 'echo $1'
[{"file":"/dev/stdin","line":1,"endLine":1,"column":6,"endColumn":8,"level":"info","code":2086,"message":"Double quote to prevent globbing and word splitting."}]
```

This change deprecates the parser's getNextId and getNextIdAt, replacing
it with a new withNextId function. This function has the type signature:

withNextId :: Monad m => ParsecT s UserState (SCBase m) (Id -> b) -> ParsecT s UserState (SCBase m) b

Specifically, it should be used to wrap read* functions and will pass in
a newly generated Id which should be used to represent that node.
Sub-parsers will need their own call to withNextId in order to get a
unique Id.

In doing this, withNextId can now track both the entry and exit position
of every read* parser which uses it, enabling the tracking of end
columns throughout the application.

This release is dedicated to Valve for keeping PC gaming awesome.
Also, for that time they proved the need for a tool like ShellCheck.

Check if builtin cd is called

Fixes #1234

Add T_SourceCommand to wrap source commands and sourced code

Fixes #1181

Handle offset references of the form [foo]:bar (fixes #1124)

Change to aeson (fixes #1085)

Whitelist rename for SC2016 (fixes #1199)