Make explicit the fact that the behavior of Fmt depends on latex_flg.

This is not a behavior change.
By inlining `__str__` into `Fmt`, it becomes clear that the logic is wrong for keeping track of `fmt` and `prev_fmt`.
This will be addressed in a future commit.

Author: eric-wieser

galgebra/mv.py

@@ -1172,7 +1172,11 @@ def Fmt(self, fmt=1, title=None):
         if printer.isinteractive():
             return self
 
-        s = str(self)
+        if printer.GaLatexPrinter.latex_flg:
+            s = printer.GaLatexPrinter().doprint(self)
+        else:
+            s = printer.GaPrinter().doprint(self)
+
         printer.GaPrinter.fmt = printer.GaPrinter.prev_fmt
         if title is not None:
             return title + ' = ' + s
@@ -1804,7 +1808,11 @@ def Fmt(self, fmt=1, title=None, dop_fmt=None):
         if printer.isinteractive():
             return self
 
-        s = str(self)
+        if printer.GaLatexPrinter.latex_flg:
+            s = printer.GaLatexPrinter().doprint(self)
+        else:
+            s = printer.GaPrinter().doprint(self)
+
         printer.GaPrinter.fmt = printer.GaPrinter.prev_fmt
         printer.GaPrinter.dop_fmt = printer.GaPrinter.prev_dop_fmt