docs: Use a separate top-level document for lAtEx

This screams about duplicate labels even *if this part isn't built!*

So we use another document that we ignore in other builders.

Blergh

doc_src/conf.py

@@ -104,7 +104,7 @@ language = None
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
 # This pattern also affects html_static_path and html_extra_path.
-exclude_patterns = []
+exclude_patterns = ["latex"]
 
 # The name of the Pygments (syntax highlighting) style to use.
 pygments_style = None
@@ -150,7 +150,7 @@ latex_elements = {
 #  author, documentclass [howto, manual, or own class]).
 latex_documents = [
     (
-        master_doc,
+        "latex",
         "fish-shell.tex",
         "fish-shell Documentation",
         "fish-shell developers",

doc_src/index.rst

@@ -183,10 +183,3 @@ If you have an improvement for fish, you can submit it via the GitHub page.
              design
              relnotes
              license
-
-.. only:: builder_latex
-
-   .. include:: tutorial.rst
-   .. include:: interactive.rst
-   .. include:: language.rst
-   .. include:: fish_for_bash_users.rst

doc_src/latex.rst

@@ -0,0 +1,7 @@
+.. only:: builder_latex
+
+   .. include:: index.rst
+   .. include:: tutorial.rst
+   .. include:: interactive.rst
+   .. include:: language.rst
+   .. include:: fish_for_bash_users.rst