Update README.rdoc [ci skip]

Highlighted code
Update commands.rb content in initialization guide

[ci skip]
Add section for command_tasks in initialization guide

[ci skip]
Change syntax format for example returned values

According to our guideline, we leave 1 space between `#` and `=>`, so we
want `# =>` instead of `#=>`.

Thanks to @fxn for the suggestion.

[ci skip]
Fix RailsServer#start content in initialization guide

[ci skip]
[ci skip] Replace #=> with # =>
Correct guide relating MiddlewareStackProxy with Enumerable

[ci skip] Enumerable.instance_methods &
Rails::Configuration::MiddlewareStackProxy.instance_methods # =>
[:as_json]

MiddlewareStackProxy does not share any notable methods with Enumerable.
Remove outdated guide on using rack builder w/o rails middleware

[ci skip]
Fix broken Wikipedia link.
Update action_controller_overview.md [ci skip]

Code style adherence
The option is called encode_big_decimal_as_string [ci-skip]
syntax error joining tables

syntax error joining tables
syntax error joining/including models

syntax error joining/including models
Revert last two commits mistakenly changing join/include syntax

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Revert "syntax error joining/including models"

This reverts commit ac35f72f30c47298a20a90c8c537db888b463bbb.

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Revert "syntax error joining tables"

This reverts commit c365986b48c3e8bc8c7f3fa6a8521616ed5dc138.

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Comments:

https://github.com/rails/docrails/commit/c365986b48c3e8bc8c7f3fa6a8521616ed5dc138#commitcomment-4630684
Improve reading / style of hashes in AR guide
Revert "Merge pull request #12990 from vipulnsward/remove_visualizer_param"

This reverts commit 5a19346d2855ecb1c791cdef3af92589566d00db, reversing
changes made to d82588ee4756b03025813b3997f4db171ee0fcdc.

This argument is being used in the view
https://github.com/rails/rails/blob/5a19346d2855ecb1c791cdef3af92589566d00db/actionpack/lib/action_dispatch/journey/visualizer/index.html.erb#L4

It is being set using the binding
https://github.com/rails/rails/blob/5a19346d2855ecb1c791cdef3af92589566d00db/actionpack/lib/action_dispatch/journey/gtg/transition_table.rb#L108
Build fix for Routing Inspector

Broken by

6701b4cf41f6f3d9cfc6a93715acbf852d1e468e
Merge pull request #12992 from arunagw/build-fix-routing-inspector

Build fix for Routing Inspector
Fix for titles of info pages

Both `rails/info/properties` and `rails/info/routes` have same html
title attribute as *Routes*. This commit includes a fix for the titles.
Merge pull request #12994 from sbagdat/fix_for_info_title

Fix for titles of info pages