Enabled word-wrap in tables

Desktop only; prevents having to scroll horizontally to see contents of larger tables
Merge pull request #3425 from druu/patch-3

[ci skip] Enabled word-wrap in tables (doc styling)
[ci skip] Add missing upgrade step from 2.1.4 to 2.2.0 in the docs
User Guide Tuning

Adjust the heading levels in the writeups for the input, loader, security and unit testing libraries, to match the other library writeups.
Specifically, the class reference section in each of these was appearing as a sub-level in the toctree, when it should be at the same level.
Signed-off-by:James L Parry <jim_parry@bcit.ca>
Merge branch 'develop' into develop-stiliyan
Merge pull request #3429 from jim-parry/userguide/fix-reference-level

User Guide Tuning
fix typo in the comments
Merge pull request #3437 from galdiolo/develop

[ci skip] fix a comment typo
Merge branch 'develop' into develop-stiliyan
Merge branch 'develop-stiliyan' of https://github.com/madwings/CodeIgniter into develop-stiliyan