css: h2 wrap instead of scroll.

[lcrilly]

Previously, h2 would scroll horizontally to accommodate very long page titles, such as ngx_http_random_index_module. This is effective but some browsers always display scrollbars, even when the title does not overflow.

As it is not possible to treat underscore as a wrappable character with the current content generator, we now wrap very long words (mid-word) when necessary. This only applies to the longest of module names (as above).

Closes #49

[nanaya]

Fwiw there's overflow-wrap: break-word which will only break long words.

[lcrilly]

@nanaya thank you - this is great.

[pluknet]

Please mention browser(s) experiencing the problem in the commit message (considering that nginx will outlive github).

[pluknet]

@lcrilly I'm not CSS expert, just note that "word-break: break-word" is different from "overflow-wrap: break-word" mentioned in #90 (comment). (Also the former is marked deprecated on MDN).