feat(rules): restrict bless to allies in a 50-ft burst

SRD spells/bless.md: 'The caster and all allies within a 50-ft. burst,
centered on the caster'. Add an AreaEffect.targets filter (all/allies/
enemies) applied where area creatures are collected; bless.json now
declares radius_ft 50 and targets allies (the caster included).

data/spells/bless.json

@@ -9,7 +9,8 @@
   "effects": [
     {
       "type": "area",
-      "radius_ft": 20,
+      "radius_ft": 50,
+      "targets": "allies",
       "save_for_half": false,
       "effects": [
         {
@@ -23,5 +24,5 @@
       ]
     }
   ],
-  "description": "All allies within 20 ft/level (modeled as a 20-ft burst applied to all creatures in area) gain a +1 morale bonus on attack rolls and on saving throws against fear effects (modeled as Will). Duration 1 min/level approximated as 10 rounds."
+  "description": "The caster and all allies within a 50-ft burst centered on the caster gain a +1 morale bonus on attack rolls and on saving throws against fear effects (modeled as Will). Duration 1 min/level approximated as 10 rounds."
 }