Fix docs link to pants_from_sources script. (Cherry-pick of pantsbuil…

…d#19088) (pantsbuild#19091)

docs/markdown/Contributions/development/running-pants-from-sources.md

@@ -24,9 +24,9 @@ Or, if you're using a `./pants` runner script, you can instead use a special `./
 
 This script expects to find a clone of the Pants repo, named `pants`, as a sibling directory of the one you're running in, and it will use the sources in that sibling to run Pants in the other repo, using that repo's config file and so on.
 
-You can find an example of this script [here](https://github.com/pantsbuild/example-python/blob/main/pants_from_sources). To copy it into your repo, use 
+You can find an example of this script [here](https://github.com/pantsbuild/example-python/blob/2.14/pants_from_sources). To copy it into your repo, use
 
 ```
-curl -L -O https://raw.githubusercontent.com/pantsbuild/example-python/main/pants_from_sources && \
+curl -L -O https://raw.githubusercontent.com/pantsbuild/example-python/2.14/pants_from_sources && \
   chmod +x pants_from_sources
 ```