[TASK] Improve maximum length for TCA text type .rst documentation

Improve the documentation file, mention IE9 is not compatible
and line breaks count as two characters.

Resolves: #64888
Related: #24906
Releases: master
Change-Id: I182734cdf9b9a01303369e88d237292d2ab861f4
Reviewed-on: http://review.typo3.org/36682


Reviewed-by: Alexander Stehlik <alexander.stehlik@gmail.com>
Tested-by: Alexander Stehlik <alexander.stehlik@gmail.com>
Reviewed-by: Daniel Maier <dani-maier@gmx.de>
Tested-by: Daniel Maier <dani-maier@gmx.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>