Update examples.mdx to include link to more regex examples (#840)

Added link to more regex examples

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Author: kilyinov

docs/code-search/queries/examples.mdx

@@ -112,3 +112,5 @@ Regex searches are also useful when searching boundaries that are not delimited
 ```sgquery
 repo:^github\.com/sourcegraph/ \bbtn-secondary\b
 ```
+
+More examples of regex searches are available [here](https://sourcegraph.com/docs/code-search/queries#regular-expression-search)