add OpenCL as a languages.json entry

[gabrielmfern]

Just added a new entry into the language.json file with the following configurations:

"OpenCL": {
  "name": "OpenCL",
  "multi_line_comments": [["/*", "*/"]],
  "extensions": ["cl", "ocl"]
},

[XAMPPRocky]

Thank you for your PR, and congrats on your first contribution! 🎉