message: generate_docs: improved help message
diff: #!/bin/bash
  -# Run with argument `--clean` for clean build and removing install dir.
  +# Run with argument `--clean` for clean build and removal of install directory.
  # exit on any error
  set -e
  @@ -19,7 +19,7 @@ Usage: ./generate_docs.sh [OPTIONS]
  2. Runs doxygen and create HTML and XML docs
  3. Runs script to generate markdown from XML
  - --clean for clean build and removing install dir.
  + --clean for clean build and removal of install directory.
  --help display this help and exit
  "
  