Bug#242782: languagechooser: Give more hints about the way to navigate in the list

[Nathanael Nerode <neroden@twcny.rr.com>]

Christian Perrier wrote:

> In the meantime, at least for the languagechooser screen, a very short
> hint would help.
> 
> I propose
> 
> Description: Choose a language
>  The language may be chosen by scrolling down this list with Up/Down keys
   s/down/through/   s,with Up/Down,with the Up Arrow and Down Arrow,
>  and hitting Enter on the one fitting your language. Only the first
  s/hitting/pressing/     s/fitting/matching/     s/first/first few/
>  entries are currently shown. Please scroll with the Down arrow for seeing
   s/Please scroll/Scroll/        s/for seeing/to see/
>  more entries.

Here's some English language template polishing in the form of sed 
replacements.  The s/for seeing/to see/ is mandatory ("for seeing" is 
incorrect here); the rest is just polishing.