I found a few sketches on GitHub that have the bug you encountered and have submitted pull requests to fix it:
- Rename file to match #include directive by per1234 · Pull Request #151 · Bodmer/TFT_eSPI · GitHub
- Rename file to match #include directive by per1234 · Pull Request #8 · neptune2/esp8266-weather-station-color-DST · GitHub
- Rename file to match #include directive by per1234 · Pull Request #7 · MarcFinns/AtmoScan · GitHub
- Rename file to match #include directive by per1234 · Pull Request #2 · fowlerk/ESP8266-Color-Weather-Station-Touchscreen-v15 · GitHub
- Rename file to match #include directive by per1234 · Pull Request #1 · anthonyjclarke/ESP8266-Color-Weather-Station-v8-TS · GitHub
However, none of them appear to match the repository name expected from the error you posted (WeatherStation). If you will post a link to where you found this code I'll go ahead and submit a fix there as well to prevent anyone else having this problem in the future.