Fix spacing on line breaks

Co-authored-by: Elliott Sales de Andrade <[email protected]>

Author: ksunden

lib/matplotlib/projections/__init__.py

@@ -60,8 +60,8 @@
     from mpl_toolkits.mplot3d import Axes3D
 except ImportError:
     import warnings
-    warnings.warn("Unable to import Axes3D. This may be due to multiple versions of"
-                  "Matplotlib being installed (e.g. as a system package and as a pip"
+    warnings.warn("Unable to import Axes3D. This may be due to multiple versions of "
+                  "Matplotlib being installed (e.g. as a system package and as a pip "
                   "package). As a result, the 3D projection is not available.")
     Axes3D = None