Use {% includes data-prep %} in ST-SP, ST-SPT
Add U example
Fix alignment
Add WDO example
Improve U SP 1 -> 4
Explain path numbering in a note
Add unreachable example
Add including geometries example
Simpify signatures
Add missing See also
Merge pull request #390 from agouge/ghp-st-sp-examples

Add examples for ST_ShortestPath