Fix typo and spell check

Author: Riandy

.github/scripts/spellcheck_conf/wordlist.txt

@@ -1556,3 +1556,8 @@ RequestBuilder
 VectorIndexManager
 csvs
 programmatically
+Customizations
+VSCode
+applyTo
+mdc
+windsurfrules

end-to-end-use-cases/coding_assistant/README.md

@@ -299,7 +299,7 @@ GitHub Copilot leverages context from open files, the workspace, or specific ins
 
 #### Optimize with Custom Rules
 - Create a .github/copilot-instructions.md file in your workspace to define general coding standards and guidelines for all Copilot chat requests.
-- For file- or task-specific rules, use .instructions.md files with the applyTo frontmatter to specify file targeting.
+- For file- or task-specific rules, use .instructions.md files with the applyTo formatter to specify file targeting.
 - You can also add settings in settings.json for review, commit message generation, and pull request description instructions, either directly or by referencing instruction files
 
 For more information, refer to https://docs.github.com/en/copilot/how-tos/configure-custom-instructions/add-repository-instructions