Bugfix: Titles, alternative texts and labels in rich text translated 

Description 

DeepL translates the content of elements, never the values of their attributes. The title an editor enters for a link in the rich text editor is stored as the title attribute of the <a>, so it stayed in the source language while the link text was translated (issue #427). Readers see the title as a tooltip and screen readers read it out.

The values of the attributes readers see or hear as text are now sent to DeepL as texts of their own, in the same request as the field:

• title of any element, for example of a link or of an abbreviation, <abbr title="World Health Organization">WHO</abbr>,
• alt of an image,
• aria-label of any element.

The translations replace the values in the translated field. DeepL keeps the attributes of every element, also when it moves an element within the sentence, so every link gets the translation of its own title. Equal values are sent once.

A value is not translated in content marked as not to be translated, with translate="no" or the class notranslate on the element or an ancestor, on <script> and <style>, and if it has no letter, like a number. A value DeepL returns unchanged, like a name, is kept as stored.

Impact 

Translated rich text has translated tooltips, alternative texts and labels. The characters of these values are billed by DeepL like the rest of the field, and the glossary and formality of the translation apply to them as well. A title holding something that must not change, like a product code, is sent too. Marked with the class notranslate, the element keeps its title and its text.

See pull request #644.