Add markerfacealt to pass-through arguments for error bar lines (matplotlib#23475)

* Add markerfacealt to pass-through arguments for error bar lines

* Update documentation to reflect which kwargs errorbar() passes on

* Document API changes

* Refactor documentation list of supported Line2D kwargs

* Update lib/matplotlib/axes/_axes.py

Fix tabbing on documentation

Co-authored-by: Tim Hoffmann <[email protected]>

Co-authored-by: Tim Hoffmann <[email protected]>

Author: wqian94

doc/api/next_api_changes/behavior/23475-WLQ.rst

@@ -0,0 +1,5 @@
+The markerfacecoloralt parameter to Line2D is now supported by axes.errorbar
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+- markerfacecoloralt is now passed to the line plotter from axes.errorbar
+- Documentation for axes.errorbar how accurately lists which properties are
+  passed on to Line2D, rather than claiming that all kwargs are passed on

lib/matplotlib/axes/_axes.py

@@ -3367,7 +3367,25 @@ def errorbar(self, x, y, yerr=None, xerr=None,
             property names, *markerfacecolor*, *markeredgecolor*, *markersize*
             and *markeredgewidth*.
 
-            Valid kwargs for the marker properties are `.Line2D` properties:
+            Valid kwargs for the marker properties are:
+
+            - *dashes*
+            - *dash_capstyle*
+            - *dash_joinstyle*
+            - *drawstyle*
+            - *fillstyle*
+            - *linestyle*
+            - *marker*
+            - *markeredgecolor*
+            - *markeredgewidth*
+            - *markerfacecolor*
+            - *markerfacecoloralt*
+            - *markersize*
+            - *markevery*
+            - *solid_capstyle*
+            - *solid_joinstyle*
+
+            Refer to the corresponding `.Line2D` property for more details:
 
             %(Line2D:kwdoc)s
         """
@@ -3467,6 +3485,7 @@ def _upcast_err(err):
         # Eject any line-specific information from format string, as it's not
         # needed for bars or caps.
         for key in ['marker', 'markersize', 'markerfacecolor',
+                    'markerfacecoloralt',
                     'markeredgewidth', 'markeredgecolor', 'markevery',
                     'linestyle', 'fillstyle', 'drawstyle', 'dash_capstyle',
                     'dash_joinstyle', 'solid_capstyle', 'solid_joinstyle',