Fixes#1329
Some shells and scripts use spaces and soft-wrapping as a way to move to
the next line instead of using newline (`\n`). Line selection
(triple-click by default) considers a soft-wrapped line as a single
line, so it was selecting the prompt.
This commit makes it so line selection considers semantic prompt state
(prompt vs command output) an additional boundary condition. This
requires shell integration but will make selection behave more
expectedly.
48d6c93e09