fix: Ruff rule RET506 (superfluous-else-raise)

https://docs.astral.sh/ruff/rules/superfluous-else-raise/

Author: bartsanchez

pyproject.toml

@@ -135,7 +135,6 @@ ignore = [
     "RET501",
     "RET503",
     "RET504",
-    "RET506",
     "RET507",
     "RUF005",
     "RUF012",

src/ply/yacc.py

@@ -893,8 +893,7 @@ def add_production(self, prodname, syms, func=None, file="", line=0):
             prodprec = self.Precedence.get(precname)
             if not prodprec:
                 raise GrammarError("%s:%d: Nothing known about the precedence of %r" % (file, line, precname))
-            else:
-                self.UsedPrecedence.add(precname)
+            self.UsedPrecedence.add(precname)
             del syms[-2:]  # Drop %prec from the rule
         else:
             # If no %prec, precedence is determined by the rightmost terminal symbol