Add CSS style override for RTD to make tables use word wrapping

(imported from commit 29007c052dd7048eaf86388a6a9715fc13f102b5)

docs/_static/theme_overrides.css

@@ -0,0 +1,10 @@
+/* override table width restrictions */
+.wy-table-responsive table td, .wy-table-responsive table th {
+    /* !important prevents the common CSS stylesheets from
+       overriding this as on RTD they are loaded after this stylesheet */
+    white-space: normal !important;
+}
+
+.wy-table-responsive {
+    overflow: visible !important;
+}

docs/conf.py

@@ -209,6 +209,10 @@ html_static_path = ['_static']
 # Output file base name for HTML help builder.
 htmlhelp_basename = 'zulip-contributor-docsdoc'
 
+def setup(app):
+    # overrides for wide tables in RTD theme
+    app.add_stylesheet('theme_overrides.css')   # path relative to _static
+
 # -- Options for LaTeX output ---------------------------------------------
 
 latex_elements = {