Add note about linguist language detection

notes/github-force-detect-language.md

@@ -0,0 +1,16 @@
+---
+title: Force GitHub to detect a language
+tags:
+  - GitHub
+---
+
+```gitattributes
+*.md linguist-detectable=true
+*.sql linguist-detectable=true
+```
+
+To force detection as a specific language:
+
+```gitattributes
+*.sql linguist-language=sql
+```