sagemathgh-38943: Some documentation improvement

    
Just improve some documentation.

Apparently the existing documentation uses the absolute URL ``   * -
`Tutorial <../tutorial/index.html>`_`` e.g.
`sage/src/doc/en/developer/sage_manuals.rst`, none of them uses
`<tutorial>`. I tried using `<chapter-tutorial>` in https://github.com/s
agemath/sage/commit/955a09e746c7d9675d2a4c4f10558cec8d3eb948 but for
some reason it doesn't work, so I just end up deleting it.

### 📝 Checklist

<!-- Put an `x` in all the boxes that apply. -->

- [x] The title is concise and informative.
- [x] The description explains in detail what this PR is about.
- [x] I have linked a relevant issue or discussion. (not aware of one)
- [x] I have created tests covering the changes.
- [x] I have updated the documentation and checked the documentation
preview.

------

test failures have nothing to do with the change, see
sagemath#37295
    
URL: sagemath#38943
Reported by: user202729
Reviewer(s): Kwankyu Lee, user202729

src/doc/en/developer/coding_in_cython.rst

@@ -32,13 +32,13 @@ up-to-date information or check out the
 to get started immediately.
 
 
-Writing cython code in Sage
+Writing Cython code in Sage
 ===========================
 
 There are several ways to create and build Cython code in Sage.
 
-#. In the Sage Notebook, begin any cell with ``%cython``. When you
-   evaluate that cell,
+#. In the Sage notebook or the Sage command line, begin any cell with
+   a line containing ``%%cython``. When you evaluate that cell,
 
    #. It is saved to a file.
 
@@ -53,22 +53,21 @@ There are several ways to create and build Cython code in Sage.
       program that was compiled to create the ``.so`` file.
 
    #. A ``cpdef`` or ``def`` function, say ``testfunction``, defined in
-      a ``%cython`` cell in a worksheet can be imported and made available
-      in a different ``%cython`` cell within the same worksheet by
+      a ``%%cython`` cell in a worksheet can be imported and made available
+      in a different ``%%cython`` cell within the same worksheet by
       importing it as shown below::
 
-          %cython
+          %%cython
           from __main__ import testfunction
 
-#. Create an ``.spyx`` file and attach or load it from the command
-   line. This is similar to creating a ``%cython`` cell in the
-   notebook but works completely from the command line (and not from
-   the notebook).
+   Refer to :meth:`sage.repl.ipython_extension.SageMagics.cython`.
+
+#. Create an ``.spyx`` file and attach or load it
+   from the command line.
 
 #. Create a ``.pyx`` file and add it to the Sage library.
    Then run ``sage -b`` to rebuild Sage.
 
-
 Attaching or loading .spyx files
 ================================
 

src/doc/en/reference/repl/index.rst

@@ -1,12 +1,14 @@
+.. _section-command-line:
+
 The Sage Command Line
 =====================
 
 The Sage Read-Eval-Print-Loop (REPL) is based on IPython. In this
 document, you'll find how the IPython integration works. You should
 also be familiar with the documentation for IPython.
 
-For more details about using the Sage command line, see the Sage
-tutorial.
+For more details about using the Sage command line, see `the Sage
+tutorial <../../tutorial/index.html>`_.
 
 Running Sage
 ------------

src/doc/en/tutorial/index.rst

@@ -2,8 +2,6 @@
    You can adapt this file completely to your liking, but it should at least
    contain the root `toctree` directive.
 
-.. _tutorial:
-
 ========================
 Welcome to Sage Tutorial
 ========================

src/sage/interacts/library.py

@@ -2,7 +2,7 @@
 Sage Interacts
 
 Sage interacts are applications of the `@interact decorator <../../sagenb/notebook/interact.html>`_.
-They are conveniently accessible in the Sage Notebook via ``interacts.[TAB].[TAB]()``.
+They are conveniently accessible in the Sage notebook via ``interacts.[TAB].[TAB]()``.
 The first ``[TAB]`` lists categories and the second ``[TAB]`` reveals the interact examples.
 
 EXAMPLES:

src/sage/misc/cython.py

@@ -578,6 +578,9 @@ def cython_import_all(filename, globals, **kwds):
 
     - ``filename`` -- string; name of a file that contains Cython
       code
+
+    See the function :func:`sage.misc.cython.cython` for documentation
+    for the other inputs.
     """
     m = cython_import(filename, **kwds)
     for k, x in m.__dict__.items():
@@ -621,6 +624,9 @@ def compile_and_load(code, **kwds):
     - ``code`` -- string containing code that could be in a .pyx file
       that is attached or put in a %cython block in the notebook
 
+    See the function :func:`sage.misc.cython.cython` for documentation
+    for the other inputs.
+
     OUTPUT: a module, which results from compiling the given code and
     importing it
 

src/sage/misc/persist.pyx

@@ -92,7 +92,7 @@ def load(*filename, compress=True, verbose=True, **kwargs):
     an ``.sobj`` extension added if it doesn't have one.  Or, if the input
     is a filename ending in ``.py``, ``.pyx``, ``.sage``, ``.spyx``,
     ``.f``, ``.f90`` or ``.m``, load that file into the current running
-    session.
+    session using :func:`sage.repl.load.load`.
 
     Loaded files are not loaded into their own namespace, i.e., this is
     much more like Python's ``execfile`` than Python's ``import``.

src/sage/plot/animate.py

@@ -839,7 +839,7 @@ def show(self, delay=None, iterations=None, **kwds):
 
             sage: a.show(delay=50)                      # long time  # optional -- ImageMagick
 
-        You can also make use of the HTML5 video element in the Sage Notebook::
+        You can also make use of the HTML5 video element in the Sage notebook::
 
             sage: # long time, optional -- FFmpeg
             sage: a.show(format='ogg')

src/sage/repl/attach.py

@@ -318,8 +318,12 @@ def attach(*files):
 
     .. SEEALSO::
 
-        :meth:`~sage.repl.load.load` is the same as :func:`attach`, but
-        does not automatically reload a file when it changes.
+        :func:`~sage.repl.load.load` is the same as :func:`attach`, but
+        does not automatically reload a file when it changes unless
+        ``attach=True`` is passed.
+
+        ``%attach`` magic can also be used, see
+        :meth:`~sage.repl.ipython_extension.SageMagics.attach`.
 
     EXAMPLES:
 

src/sage/repl/ipython_extension.py

@@ -107,6 +107,10 @@ def runfile(self, s):
 
         - ``s`` -- string; the file to be loaded
 
+        .. SEEALSO::
+
+            This is the same as :func:`~sage.repl.load.load`.
+
         EXAMPLES::
 
             sage: import os
@@ -133,6 +137,10 @@ def attach(self, s):
 
         - ``s`` -- string. The file to be attached
 
+        .. SEEALSO::
+
+            This is the same as :func:`~sage.repl.attach.attach`.
+
         EXAMPLES::
 
             sage: from sage.repl.interpreter import get_test_shell

src/sage/repl/load.py

@@ -87,6 +87,14 @@ def load(filename, globals, attach=False):
 
             from t import *
 
+    .. NOTE::
+
+        The global ``load`` function is :func:`sage.misc.persist.load`,
+        which delegates to this function for code file formats.
+
+        ``%runfile`` magic can also be used, see
+        :meth:`~sage.repl.ipython_extension.SageMagics.runfile`.
+
     INPUT:
 
     - ``filename`` -- string (denoting a filename or URL) or a :class:`Path` object
@@ -97,13 +105,15 @@ def load(filename, globals, attach=False):
     - ``attach`` -- boolean (default: ``False``); whether to add the
       file to the list of attached files
 
-    Loading an executable Sage script from the command prompt will run whatever
-    code is inside an
+    Loading an executable Sage script from the :ref:`command line <section-command-line>`
+    will run whatever code is inside an
+
+    ::
 
         if __name__ == "__main__":
 
     section, as the condition on ``__name__`` will hold true (code run from the
-    command prompt is considered to be running in the ``__main__`` module.)
+    command line is considered to be running in the ``__main__`` module.)
 
     EXAMPLES:
 
@@ -159,7 +169,8 @@ def load(filename, globals, attach=False):
 
         sage: sage.repl.load.load('https://raw.githubusercontent.com/sagemath/sage-patchbot/3.0.0/sage_patchbot/util.py', globals())  # optional - internet
 
-    We attach a file::
+    We attach a file (note that :func:`~sage.repl.attach.attach`
+    is equivalent, but available at the global scope by default)::
 
         sage: t = tmp_filename(ext='.py')
         sage: with open(t, 'w') as f: