Fix broken links to source

[fordhurley]

Fixes #14819

This was noted in #14750 (comment).

The problem was that the [path] for the docs changed to support localization, but the source code didn't. For example, /docs/#api/objects/Mesh became /docs/#api/en/objects/Mesh.

The doc links follow the pattern:

[link:https://github.com/mrdoob/three.js/blob/master/src/[path].js src/[path].js]

where [path] is, for our example, en/objects/Mesh.

I introduced a new variable, [nonLocalizedPath], and changed the links to:

[link:https://github.com/mrdoob/three.js/blob/master/src/[nonLocalizedPath].js src/[nonLocalizedPath].js]

Not an elegant solution, but it gets the job done. Extremely open to other approaches.

[fordhurley]

A more elegant solution might be to completely DRY the links in the docs by defining the whole link as a variable, e.g. [linkToSource].

[mrdoob]

I think [path] is only used for these links.

Instead of modifying all the files, I think you should be able just remove the /en part in this line:

https://github.com/mrdoob/three.js/blob/dev/docs/page.js#L56

text = text.replace( /\[path\]/gi, path.substr( 3 ) );

[fordhurley]

Ok, great! I was afraid there would be a reason to keep the full [path] around, but this is dramatically simpler. I just opened a new PR with that solution: #14846