fix loading of language name from kernel_info

language is langinfo.name, not langinfo.language

fixes highlighting for IJulia kernels
move language name, version into language_info

in kernel_info_reply

adds adaptation of language info to msgspec adapter
add language_info to nbformat doc and spec
update kernel_info_reply test
validate codemirror_mode
Always depend on gnureadline if setupext.check_for_readline() fails

The inconsistency (asymmetry) of unconditionally adding gnureadline as a
dependency of binary distributions can cause issues like reported at
https://github.com/paylogic/pip-accel/issues/34
Move js donc into function themselves.

Then it is possible in the browser js console to get the documentation
interactively.
Add docstring documentation for widget_float
close pager on escape on command mode
Added changes to dosctring documentation in widget_float.py (previous docstring written by me).
Added docstring documentation in widget_bool.py.
Merge pull request #7068 from Carreau/close-pager

close pager on escape on command mode
use less variable for rounded corner

and allow none in versions comparison
Removed the two empty lines of dosctring in widget_float.py.
Depend on gnureadline when building binary wheel or setupext.check_for_readline() fails

This is a follow up to 4d9f6f00a4f0798e41700c22a839eddff0881692 based on
the discussion in pull request #7047 where we seem to have found a middle
ground that should make everyone happy :-)
Merge pull request #7059 from silviav12/widget_docstring

Add docstring documentation for widget_float
Merge pull request #6945 from minrk/kernel-info-lang

fix loading of language name from kernel_info
Merge pull request #7047 from xolox/setup-gnureadline-fix

Only force gnureadline in setup.py with bdist_wheel

instead of all bdists
Merge pull request #7007 from Carreau/less-update

Less update
Adapt headers to using Content Security Policy
Document Content-Security-Policy changes