gh-40954: Update README.md to reflect the current status better
    
in particular, remove a mention of `venv/bin/` (a confusion arose on
[sage-devel](https://groups.google.com/g/sage-
devel/c/t5Nxu61MhMI/m/m9S0GRU9AwAJ)) and explain how to get html docs.


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- [x] The description explains in detail what this PR is about.
- [x] I have linked a relevant issue or discussion.
- [ ] I have created tests covering the changes.
- [ ] I have updated the documentation and checked the documentation
preview.

### ⌛ Dependencies

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URL: #40954
Reported by: Dima Pasechnik
Reviewer(s): Dima Pasechnik, Sahil Jain, Tobias Diez

Author: Release Manager

README.md

@@ -411,8 +411,8 @@ in the Installation Guide.
     If there are numerous failures, there was a serious problem with your build.
 
 17. The HTML version of the [documentation](https://doc.sagemath.org/html/en/index.html)
-    is built during the compilation process of Sage and resides in the directory
-    `local/share/doc/sage/html/`. You may want to bookmark it in your browser.
+    can be built by running `make doc-html` and resides in
+    `build/sage-distro/src/doc/`. You may want to bookmark it in your browser.
 
 18. Optional: If you want to build the PDF version of the documentation,
     run `make doc-pdf` (this requires LaTeX to be installed).
@@ -427,7 +427,7 @@ in the Installation Guide.
     having to either type the full path or navigate to the Sage
     directory and type `./sage`. This can be done by running:
 
-        $ sudo ln -s $(./sage -sh -c 'ls $SAGE_ROOT/venv/bin/sage') /usr/local/bin
+        $ sudo ln -s $(pwd)/sage /usr/local/bin
 
 21. Optional: Set up SageMath as a Jupyter kernel in an existing Jupyter notebook
     or JupyterLab installation, as described in the section