Fix settings for customization

Author: ntrogh

docs/copilot/copilot-settings.md

@@ -51,7 +51,10 @@ The team is continuously working on improving Copilot in VS Code and adding new
 
 ## Customize Copilot prompts
 
-c
+* `setting(github.copilot.chat.codeGeneration.instructions)` <i class="codicon codicon-beaker"></i>: A set of instructions that will be added to Copilot requests that generate code.
+* `setting(github.copilot.chat.codeGeneration.useInstructionFiles)` _(Preview)_: Controls whether code instructions from `.github/copilot-instructions.md` are added to Copilot requests.
+* `setting(github.copilot.chat.testGeneration.instructions)` <i class="codicon codicon-beaker"></i>: A set of instructions that will be added to Copilot requests that generate tests.
+
 ## Debugging settings
 
 * `setting(github.copilot.chat.startDebugging.enabled)` _(Preview)_: Enables the experimental `/startDebugging` intent in the Chat view to generate debugging configuration.