Maybe this helps: Anywhere there is a colon ( this symbol : ) it means that all numbers are included between. For example, the phrase b2:b6 means all numbers, b2, b3, b4, b5, b6. When they add a comma and another number, it means this : b2:b6,b9 = b2, b3, b4, b5, b6, b9.
This is done to save writting ( and drawing ) all the connections identified.
This is common practice in schematics, to save alot of redundant lines that connect everywhere, or are connected to alot of common elements. For example, if you had a data bus 64 connections wide, you would draw a single line, and label it something like D1
64. This makes the schematic far cleaner, and ( supposedly ) easier to read.
In your case, the LED connections are shown with a single wire, representing several connections, as in chip pins # RA0:RA3,RA5 ( representing RA0, RA1, RA2 RA3, RA5 ) are, pin numbers 2:5,7 ( pins 2,3,4,5,7 ) connect to the LED segments a:d,f ( a, b, c, d, f )
This way, one line on the drawing, three labels, all meaning 5 wires. It saves clutter.
Hope this helps.