[feature] Add 'Custom Expression' numeric format (Request in QGIS)

[qgis-bot]

Request for documentation

From pull request qgis/QGIS#58492
Author: @nyalldawson
QGIS version: 3.40

[feature] Add 'Custom Expression' numeric format

PR Description:

This numeric format allows users to craft a custom QGIS expression to format numbers. The expression can use the @value variable to retrieve the value to be formatted, and then use any standard QGIS expression function to format this as desired.

It can be used anywhere QgsNumericFormat is accepted, eg layout scalebars, elevation plots, layout tables, and color ramp legends

Sponsored by the Swiss QGIS User Group

Commits tagged with [need-docs] or [FEATURE]

"[feature] Add 'Custom Expression' numeric format\n\nThis numeric format allows users to craft a custom QGIS expression\nto format numbers. The expression can use the @value variable\nto retrieve the value to be formatted, and then use any standard\nQGIS expression function to format this as desired.\n\nIt can be used anywhere QgsNumericFormat is accepted, eg layout\nscalebars, elevation plots, layout tables, and color ramp\nlegends\n\nSponsored by the Swiss QGIS User Group"