Update github-vs-sourcegraph.mdx (#937)

The current links are for a repo which no longer exists or is no longer
public (sourcegraph/sourcegraph), so the example links return 0 results.

This change uses an existing repository for the example search
([sourcegraph/about](https://github.com/sourcegraph/about)).

<details><summary>Before</summary>


![image](https://github.com/user-attachments/assets/f74991bd-810a-40e2-9ec0-e0e84c58e32f)

</details> 

<details><summary>After</summary>


![image](https://github.com/user-attachments/assets/b633a5d7-0ce4-4bab-8458-d29acb69839d)

</details> 


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Author: LeweyM

docs/getting-started/github-vs-sourcegraph.mdx

@@ -115,7 +115,7 @@ In addition to searching your organization’s private code, you can use Sourceg
 
 ### Search syntax
 
-Sourcegraph offers [structural search](/code-search/types/structural), and GitHub code search does not offer this search method. Structural search lets you match richer syntax patterns, specifically in code and structured data formats like JSON. Sourcegraph offers structural search on indexed code and uses [Comby syntax](https://comby.dev/docs/syntax-reference) for structural matching of code blocks or nested expressions. For example, the `fmt.Sprintf` function is a popular print function in Go. [Here](https://sourcegraph.com/search?q=repo:%5Egithub%5C.com/sourcegraph/sourcegraph%24+fmt.Sprintf%28...%29&patternType=structural&_ga=2.204781593.827352295.1667227568-1057140468.1661198534&_gac=1.118615675.1665776224.CjwKCAjwkaSaBhA4EiwALBgQaJCOc6GlhIDQyg6HQScgfSBQpoFTUf7T_NNqEX5JaobtCS08GUEJuRoCIlIQAvD_BwE&_gl=1*1r2u5zs*_ga*MTA1NzE0MDQ2OC4xNjYxMTk4NTM0*_ga_E82CCDYYS1*MTY2NzUwODExNC4xMTQuMS4xNjY3NTA5NjUyLjAuMC4w) is a pattern that matches all of the arguments in `fmt.Sprintf` in our code using structural search compared to the [search](https://sourcegraph.com/search?q=context:global+repo:%5Egithub%5C.com/sourcegraph/sourcegraph%24+fmt.Sprintf%28...%29&patternType=regexp) using regex.
+Sourcegraph offers [structural search](/code-search/types/structural), and GitHub code search does not offer this search method. Structural search lets you match richer syntax patterns, specifically in code and structured data formats like JSON. Sourcegraph offers structural search on indexed code and uses [Comby syntax](https://comby.dev/docs/syntax-reference) for structural matching of code blocks or nested expressions. For example, the `fmt.Sprintf` function is a popular print function in Go. [Here](https://sourcegraph.com/search?q=repo:%5Egithub%5C.com/sourcegraph/about%24+fmt.Sprintf%28...%29&patternType=structural&_ga=2.204781593.827352295.1667227568-1057140468.1661198534&_gac=1.118615675.1665776224.CjwKCAjwkaSaBhA4EiwALBgQaJCOc6GlhIDQyg6HQScgfSBQpoFTUf7T_NNqEX5JaobtCS08GUEJuRoCIlIQAvD_BwE&_gl=1*1r2u5zs*_ga*MTA1NzE0MDQ2OC4xNjYxMTk4NTM0*_ga_E82CCDYYS1*MTY2NzUwODExNC4xMTQuMS4xNjY3NTA5NjUyLjAuMC4w) is a pattern that matches all of the arguments in `fmt.Sprintf` in our code using structural search compared to the [search](https://sourcegraph.com/search?q=context:global+repo:%5Egithub%5C.com/sourcegraph/about%24+fmt.Sprintf%28...%29&patternType=regexp) using regex.
 
 Both GitHub code search and Sourcegraph support regular expression and keyword search. [Regular expression](/code-search/queries#standard-search) helps you find code that matches a pattern (including classes of characters like letters, numbers, and whitespace) and can restrict the results to anchors like the start of a line, the end of a line, or word boundary. Keyword search matches on individual terms, supporting both literal searches and flexible keyword-style queries.