Lower maximum value for guard-extreme-restriction-percent to 100.

Values greater than 100 would have had the same effect as 100, so
this doesn't actually change Tor's behavior; it just makes the
intent clearer.  Fixes #40486; see also torspec#66.

changes/bug40486

@@ -0,0 +1,5 @@
+  o Code simplification and refactoring:
+    - Lower the official maximum for "guard-extreme-restriction-percent" to
+      100. This has no effect on when the guard code will generate a warning,
+      but it makes the intent of the option clearer.  Fixes bug 40486; bugfix
+      on 0.3.0.1-alpha.

src/feature/client/entrynodes.c

@@ -559,7 +559,7 @@ get_extreme_restriction_threshold(void)
   int32_t pct = networkstatus_get_param(NULL,
                                         "guard-extreme-restriction-percent",
                                         DFLT_EXTREME_RESTRICTION_PERCENT,
-                                        1, INT32_MAX);
+                                        1, 100);
   return pct / 100.0;
 }