Repository: ManimCommunity/manim

Issue:
Broken source links on the stable version of the documentation
## Description of bug / unexpected behavior
Source links on the stable version of documentation does not work. It links to something like this: https://github.com/ManimCommunity/manim/blob/stable/manim/mobject/changing.py which is a 404 error. 

## Expected behavior
Source links should link to a file containing source code for the stable version. 

## How to reproduce the issue
On the documentation website, switch the version to stable. Navigate to and click the source link of any class. 

## Additional comments
Perhaps this is an access rights issue, which explains why it evaded detection from community devs for so long?



Discussion:
The `stable` branch does not exist, that's why it showing the 404. @ManimCommunity/docs ?
Indeed, an oversight after getting rid of the `stable` branch. Can be fixed similarly to what is done here: https://github.com/ManimCommunity/manim/blob/6744c48c228c866c8f2256a7a2cd461bde6d411e/docs/source/conf.py#L118 -- possibly also just by linking to master, so adding `or ... == "stable"` to that line.

Sounds like an easy PR, does anyone here want to take care of it? :-)
I would like to do the PR (i am learning)
allow me?
> I would like to do the PR (i am learning)
> allow me?

Of course, please go ahead! :-)
I am not part of the project, is that why it does not allow me to do the PR? (sorry if I bother, I'm just learning and wanted to do my first PR)
![image](https://user-images.githubusercontent.com/68663197/108603885-2f86a880-7389-11eb-9964-62ec313fd5a4.png)

Please don't worry! Usually, the workflow with Github is a bit different: you create a pull request from your fork of the `ManimCommunity/manim` repository.

To create your fork, head to https://github.com/ManimCommunity/manim and look for the fork button on the top right of the page.
and from the fork I do the PR?
> and from the fork I do the PR?

Exactly. You can then choose to PR from your fork to the master branch of this repository.
can do it! also I was missing the title (it's my first time)
you are so friendly.  thank you very much for your help. I learned from this experience :)
I believe you accidentally made the PR to 3b1b/manim's master branch instead of ManimCommunity/manim's master branch:
![image](https://user-images.githubusercontent.com/29168469/108613270-20155880-73a5-11eb-975a-22a2b808c994.png)

thus there's a lot of merge conflicts (since 3b1b's version of manim is different). You should close the PR to 3b1b and make sure you're trying to merge your commits into ManimCommunity:master.
Is right. thanks for warning and sorry for the confusion
 I apologize, especially to @behackl, whoever gave me the opportunity to do the PR. but I can't do it correctly. I'm going to let someone with more experience than me do it. sorry for the loss of time and inconvenience. I must study more github
>  I apologize, especially to @behackl, whoever gave me the opportunity to do the PR. but I can't do it correctly. I'm going to let someone with more experience than me do it. sorry for the loss of time and inconvenience. I must study more github

Is there anything we can do to help you with getting started?

Resolving patch:
diff --git a/docs/source/conf.py b/docs/source/conf.py
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -115,7 +115,7 @@ def linkcode_resolve(domain, info):
         return None
     filename = info["module"].replace(".", "/")
     version = os.getenv("READTHEDOCS_VERSION", "master")
-    if version == "latest":
+    if version == "latest" or version == "stable":
         version = "master"
     return f"https://github.com/ManimCommunity/manim/blob/{version}/{filename}.py"
 


Test patch: