modifies text content of accessibility information keys

[gautierchomel]

Very partial update implementation of display guide 2.0. See #2536

[llemeurfr]

@gautierchomel do you insist having long a11y descriptions in Thorium? We only have limited space in the Information modal box, not a large HTML page, as some retailers propose on their websites.
You're the a11y expert, therefore you will choose, but my warning is that with the long descriptions, the Information box will be bloated with a11y information (when it exists for the book).

[gautierchomel]

current available space seems large enough

[gautierchomel]

This is how it looks on the shorter possible screen (first screen shot is a standard ebook while the second one is the all informations testing ebook). In both cases, it does not adds a line. To me it's a better use of the space (less white space on the right).

[gautierchomel]

In any case, it a a very partial and temporary implementation of the new guide, only shifting the existing words to ship something in the Thorium 3.1 instead of remaining with the old wording.

Full guide implementation will need more work as it comes with variants values for each keys (Readable in read aloud or dynamic braille; May not be fully readable in read aloud or dynamic braille; Not fully readable in read aloud or dynamic braille; No information is available).