Reword p_astro paragraph for terseness
Reword the p_astro statement to improve terseness, use an apporpriate number of digits, and keep it near the closely related em_bright paragraph.
Note that I added a macro to render very high probabilities as ">99%" and very low probabilities as "<1%", which is now used in both the p_astro and the em_bright paragraphs.
The text was:
The categorical astrophysical probabilities for the candidate
event as computed by the P_astro pipeline are:
BNS probability: 0.8593197490253501
BBH probability: 0.0
NSBH probability: 0.0
Terrestrial probability: 0.1406802509746499
The text is now:
The classification of the signal, in order of descending confidence,
is BNS (78%), terrestrial (22%), BBH (<1%), or NSBH (<1%).