Fixes typo

docs/data-tools/index.md

@@ -9,7 +9,7 @@ by third-parties rather than the ARCHER2 service are marked with *):
 - [AMD μProf](amd-uprof.md): Profiling tools provided by AMD
 - [Arm Forge](arm-forge.md): Provides debugging and profiling tools for MPI parallel applications, and
 OpenMP or pthreads mutli-threaded applications (and also hydrid MPI/OpenMP)
-- [Darshan](darshan.md): Lightweight IO charachterisation and profiling tool
+- [Darshan](darshan.md): Lightweight IO characterisation and profiling tool
 - [Energy Counters](pm-mpi-lib.md): MPI-based library for reading energy counters
 - [Julia(*)](julia.md): The julia language
 - [ParaView](paraview.md): A data visualisation and analysis package