Cleans documentation for `generators.line`.
Cleans documentation for `generators.line`.

Cleans formatting and syntax for the `networkx.generators.line`
module. Also moves discussion of self-loops from module-level to
function-level.

jcurbelo/networkx,NvanAdrichem/networkx,blublud/networkx,jakevdp/networkx,ionanrozenfeld/networkx,farhaanbukhsh/networkx,bzero/networkx,SanketDG/networkx,sharifulgeo/networkx,dmoliveira/networkx,Sixshaman/networkx,ionanrozenfeld/networkx,michaelpacer/networkx,bzero/networkx,harlowja/networkx,beni55/networkx,dhimmel/networkx,cmtm/networkx,yashu-seth/networkx,ghdk/networkx,sharifulgeo/networkx,dmoliveira/networkx,jakevdp/networkx,aureooms/networkx,jfinkels/networkx,ghdk/networkx,nathania/networkx,wasade/networkx,blublud/networkx,chrisnatali/networkx,OrkoHunter/networkx,blublud/networkx,goulu/networkx,chrisnatali/networkx,aureooms/networkx,harlowja/networkx,harlowja/networkx,andnovar/networkx,RMKD/networkx,debsankha/networkx,kernc/networkx,dhimmel/networkx,debsankha/networkx,chrisnatali/networkx,RMKD/networkx,jakevdp/networkx,sharifulgeo/networkx,RMKD/networkx,dhimmel/networkx,dmoliveira/networkx,farhaanbukhsh/networkx,nathania/networkx,ltiao/networkx,JamesClough/networkx,kernc/networkx,bzero/networkx,kernc/networkx,tmilicic/networkx,farhaanbukhsh/networkx,ghdk/networkx,aureooms/networkx,nathania/networkx,ionanrozenfeld/networkx,debsankha/networkx