Updated Troubleshooting (markdown)

Troubleshooting.md

@@ -28,6 +28,10 @@ If character is missing, you’ll see glyphs from a fallback font chosen by your
 
 Issues: [#812](https://github.com/tonsky/FiraCode/issues/812), [#811](https://github.com/tonsky/FiraCode/issues/811), [#800](https://github.com/tonsky/FiraCode/issues/800), [#796](https://github.com/tonsky/FiraCode/issues/796)
 
+## Font looks blurry/bad on Linux/Windows
+
+Make sure you installed TTF, not OTF files. Issues: [#798]https://github.com/tonsky/FiraCode/issues/798#issuecomment-579094899)
+
 ## Hinting issues
 
 Known problem, can’t be easily fixed.