* [DOCS] Rewrite analysis intro. Move index/search analysis content.
* Rewrites 'Text analysis' page intro as high-level definition.
Adds guidance on when users should configure text analysis
* Rewrites and splits index/search analysis content:
* Conceptual content -> 'Index and search analysis' under 'Concepts'
* Task-based content -> 'Specify an analyzer' under 'Configure...'
* Adds detailed examples for when to use the same index/search analyzer
and when not.
* Adds new example snippets for specifying search analyzers
* clarifications
* Add toc. Decrement headings.
* Reword 'When to configure' section
* Remove sentence from tip
Adds a 'Configure text analysis' page to house tutorial content for the
analysis topic.
Also relocates the following pages as children as this new page:
* 'Test an analyzer'
* 'Configuring built-in analyzers'
* 'Create a custom analyzer'
I plan to add a tutorial for specifying index-time and search-time
analyzers to this section as part of a future PR.
James Rodewig