fix spelling of titles with slashes

This is to follow the rules of the CMOS (see https://www.chicagomanualofstyle.org/qanda/data/faq/topics/Punctuation/faq0096.html)

data/presets/leisure/pitch/athletics/discus_throw.json

@@ -17,5 +17,5 @@
         "Discus Ring",
         "Discus Sector"
     ],
-    "name": "Discus Ring / Sector"
+    "name": "Discus Ring/Sector"
 }

data/presets/leisure/pitch/athletics/hammer_throw.json

@@ -17,5 +17,5 @@
         "Hammer Throw Ring",
         "Hammer Throw Sector"
     ],
-    "name": "Hammer Throw Ring / Sector"
+    "name": "Hammer Throw Ring/Sector"
 }

data/presets/leisure/pitch/athletics/shot_put.json

@@ -17,5 +17,5 @@
         "Shot Put Ring",
         "Shot Put Pit"
     ],
-    "name": "Shot Put Ring / Pit"
+    "name": "Shot Put Ring/Pit"
 }

data/presets/leisure/sports_centre.json

@@ -29,5 +29,5 @@
         "sports centre",
         "sports complex"
     ],
-    "name": "Sports Center / Complex"
+    "name": "Sports Center/Complex"
 }