Allow authentication header to not have to specify 'token=' key.

Fixes: https://github.com/rails/rails/issues/17108.
Correct test description for large integer test
[Testing guide] Use "Fixtures API" instead of "fixture api".
[Testing guide] Using "Fixtures API" consistently

- In guides, "API" is used consistently instead of "api".
- Reason behind replacing "fixtures API" to "Fixtures API" is because
  here we are referring to the concept of "fixtures". In other places in
  the guide "fixture" OR "fixtures" is referred to the single or
  multiple instances of test data.
- This is also followup of https://github.com/rails/docrails/commit/aa9d1332b20305dd860b21a7ada06c5252bebad5#commitcomment-8497376.
Explain that default_scope also influences update_all

This was not explicitly stated before and I needed to try it out to be
certain. A little explicit statement in the API docs might help here.
Fixing documentation in JSON#from_json

Commit d67b289 introduced a tiny regression in the docs for #from_json,
true needs to be included when the root node is present.
Wrap code snippets in +, not backticks, in sdoc

I grepped the source code for code snippets wrapped in backticks in the comments
and replaced the backticks with plus signs so they are correctly displayed in
the Rails documentation.

[ci skip]
raise a better exception for renaming long indexes
Remove is_a? check when ignoring tables

Technically changes the API, as it will allow any object which responds
to `===`. Personally, I think this is more flexible.
if you want to ignore all the logfiles, no need for extensions
Merge pull request #17700 from ShunsukeAida/ignore_log_as_a_whole

why not gitignore /log as a whole?

[ci skip]
ignore all logfiles but keep the log directory. #17700 [ci skip]

We generate a `.keep` file inside the log directory to make
sure the directory itself is under version control. let's keep
it that way.

/cc @matthewd
Fix select_tag generating tag when set to false.

Fixes https://github.com/rails/rails/issues/17701.
Merge pull request #17695 from claudiob/replace-all-backticks-with-pluses

Wrap code snippets in +, not backticks, in sdoc [ci skip]
Update grammar in Getting Started Guide [ci skip]
Merge pull request #17704 from fgo/patch-13

Update grammar in Getting Started Guide [ci skip]
make it possible to access fixtures excluded by a `default_scope`.

Prior to this patch you'd end up with an error like:

```
ActiveRecord::RecordNotFound: Couldn't find <Model> with 'id'=<id> [WHERE (<default_scope condition>)]
```
Merge pull request #17702 from tgxworld/fix_select_tag_include_blank_false

Fix select_tag generating tag when set to false.
Move 'the' outside of SQLite and Bundler link text [ci skip]
Fix includes on association with a scope containing joins along with conditions
on the joined assoiciation