update the link guidance now that we suppress them automatically

Author: nedbat

documentation/style-guide.rst

@@ -193,16 +193,15 @@ the second mention is more appropriate for a link.  Some units are long enough
 to have a few repeated links.  Use judgement to decide when a link will help
 the reader.
 
-Do not use a link when the link would point to the current unit.  It's natural
-to use the name of a function in the documentation for the function, but a link
-on that function name that simply reloads the section the user is already
-reading is useless and distracting.
+We use a Sphinx extension to suppress links within a section to the same
+section. Previously, editors had to carefully use an exclamation mark in a
+Sphinx reference (``:func:`!map```) to prevent such links.
 
 Do not use links in section headers.  They distract from the title of the
 section.  The term will be mentioned in the paragraph text and can be linked
 from there.
 
-Sphinx provides ways to automatically add links to references, and a way to
+Sphinx automatically adds links to references, and a way to
 suppress the link.  Using roles like ``:func:`map``` will link to the
 documentation for ``map``.  You can suppress the link while keeping the
 semantic presentation of the function name by adding an exclamation point