man: Fix several whitespace formatting issues

[diederikdehaas]

Fix the following whitespace formatting issues:

• Indentation in scdoc source files should be done with tabs.
• Lines where there (clearly) should be a line break, need to have '++' at the end, but several were missing them.
• The scdoc manual (clearly) states that lines should be hard wrapped at 80 columns, but when line(s) are indented, that causes rendering issues. So lines where a line break was not clearly intended or clearly not intended, have been put onto 1 line to circumvent the rendering issue.

Link: https://lists.sr.ht/~sircmpwn/public-inbox/%3C8251560.T7Z3S40VBb%40bagend%3E