Typo fix

Author: Robinlovelace

DESCRIPTION

@@ -26,7 +26,7 @@ Description: Tools for transport planning with an emphasis on spatial
     transport data and non-motorized modes.
     The package was originally developed to support the 'Propensity to Cycle Tool', a publicly available strategic cycle network planning tool
     (Lovelace et al. 2017) <doi:10.5198/jtlu.2016.862>, but has since been
-    extended to support public transport routing and accessiblity analysis
+    extended to support public transport routing and accessibility analysis
     (Moreno-Monroy et al. 2017) <doi:10.1016/j.jtrangeo.2017.08.012> and
     routing with locally hosted routing engines such as 'OSRM'
     (Lowans et al. 2023) <doi:10.1016/j.enconman.2023.117337>.