Add text hard wrapping

[JLiu1272]

Worked on this issue - #521

• All codemirror-based editors support this behavior. Hence, this feature is supported in /code and /markdown.
• This feature can be enabled/disabled in settings. If it is enabled, you can set the width at which the text will wrap.

Test Cases

• Check if disabling this feature work as expected. Tested by disabling it in setting, and seeing if /code /markdown actually works without wrapping.
• Check if enabling this feature work as expected. Tested by disabling it in setting, and seeing if /code /markdown actually works with wrapping.
• Toggled the width to see if it works as expected. Tested by changing the width in setting, and console logged setting to see if the width was set correctly. Repeated this test for both /code and /markdown

[JLiu1272]

Made it so that when this feature is disabled, the input to change the width for wrapping is also disabled, and vice versa.

[ansuz]

Hi,

I finally got around to reviewing and testing this in more depth. I made some changes in the process. I added some comments (via GitHub's UI, not in the code) which explain my reasoning.

This PR does exactly what it's supposed to do when editing alone, however, I found that it introduces some problematic behaviour in collaborative editing sessions. The on('change', ... handler is triggered when a change is made to the editor, but that doesn't distinguish between changes you made and those which were made by remote editors.

The consequence of this is that if one person joins an editing session with hard-wrapping enabled their client will wrap lines according to their preferences any time anybody makes a change, which could be very disruptive.

Another way to approach this is to allow users to set their preferred wrapping width in settings and to apply that to documents that they create, but to provide an additional setting for individual documents that

1. enables this to be easily enabled/disabled.
2. ensures that clients agree on the formatting of the shared document

We do this to some degree for the author colors functionality.

[JLiu1272]

Hi, sorry, got wrapped up with other things. Thanks for the feedback!