Unified SHOW page prototype

[JPryce-Aklundh]

A suggestion to make our docs for the various SHOW commands more consistent and easier to maintain.

[renetapopova]

Left some comments on the SHOW page.

[renetapopova]

Suggested change

	Rules pertaining to specific `SHOW` commands, as well as the different columns returned by them, are listed elsewhere in the documentation:
	Rules pertaining to specific `SHOW` commands, as well as the different columns returned by them, are listed on other pages or in the Operations Manual as follows:

[renetapopova]

Suggested change

	* link:{neo4j-docs-base-uri}/operations-manual/current/authentication-authorization/attribute-based-access-control/#_listing_auth_rules[`SHOW AUTH RULES` (Operations Manual)]
	* link:{neo4j-docs-base-uri}/operations-manual/current/authentication-authorization/attribute-based-access-control/#_listing_auth_rules[Operations Manual -> `SHOW AUTH RULES`]

[renetapopova]

This is the standard we follow when referring to other manuals, if you want to keep it here as well. The same will apply to the rest of the links.

[JPryce-Aklundh]

Yes, but here I think it makes it more difficult to follow - it is easier to follow the alphabetical order if "Ops Manual" is not inserted before most entries. So I will leave this as is.

[renetapopova]

I think we decided some time ago not to start pages or sections with This page outlines, this section shows, etc.
Maybe you can say something like

Suggested change

	This section lists the behavior and rules common to all `SHOW` commands.
	All `SHOW` commands have similar behavior and comply to the same rules.

[renetapopova]

Suggested change

	All `SHOW` commands have default return columns, and most have non-default return columns as well (for information about the specific columns, visit the documentation for the specific `SHOW` command listed above).
	All `SHOW` commands have default return columns, and most have non-default return columns as well.
	For information about the specific columns, see the documentation for the specific `SHOW` command listed in <<show-commands-documentation, Table 1. Show commands documentation links>>.

[renetapopova]

Suggested change

	To return non-default columns, `YIELD` must be used either to return only specific columns or all available columns.
	Using `YIELD` returns non-default columns, either specific columns or all available columns.

[renetapopova]

Suggested change

	[NOTE]
	====
	When combining a `SHOW` command with other clauses, the `YIELD` clause is mandatory and must not be omitted.
	In addition, `YIELD *` is not permitted.
	Instead, the `YIELD` clause needs to explicitly list the yielded columns.
	The query must also end with a valid last clause (like a `RETURN` or an updating clause).
	====
	[NOTE]
	====
	When combining a `SHOW` command with other clauses, the `YIELD` clause is mandatory and must not be omitted.
	`YIELD` must explicitly list the yielded columns.
	`YIELD *` is not permitted.
	The query must also end with a valid last clause (like a `RETURN` or an updating clause).
	====

[neo4j-docops-agent]

This PR includes documentation updates
View the updated docs at https://neo4j-docs-cypher-1531.surge.sh

New pages:

• SHOW
• Show functions

Updated pages:

• Clauses
• Functions