Merge pull request #4610 from matrix-org/t3chguy-patch-1

Update code style to mention switch statements

Author: t3chguy

code_style.md

@@ -151,6 +151,7 @@ General Style
   Don't set things to undefined. Reserve that value to mean "not yet set to anything."
   Boolean objects are verboten.
 - Use JSDoc
+- Use switch-case statements where there are 5 or more branches running against the same variable.
 
 ECMAScript
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