Fix minor English typos in dialogs (#2668)

locales/en/translation.json

@@ -56,7 +56,7 @@
   "Are you sure you want to reset all keyboard bindings?": "Are you sure you want to reset all keyboard bindings?",
   "Are you sure?": "Are you sure?",
   "Ask about importing chapters from opened file?": "Ask about importing chapters from opened file",
-  "Ask about what to do when opening a new file when another file is already already open?": "Ask about what to do when opening a new file when another file is already already open",
+  "Ask about what to do when opening a new file when another file is already already open?": "Ask about what to do when opening a new file when another file is already open",
   "Ask for confirmation when closing app or file?": "Ask for confirmation when closing app or file",
   "At least one codec is not supported by the selected output file format. Try another output format or try to disable one or more tracks.": "At least one codec is not supported by the selected output file format. Try another output format or try to disable one or more tracks.",
   "At least one resulting file name contains invalid character(s): {{invalidChars}}": "At least one resulting file name contains invalid character(s): {{invalidChars}}",
@@ -136,7 +136,7 @@
   "Convert current file to supported format": "Convert current file to supported format",
   "Convert markers to segments": "Convert markers to segments",
   "Convert segments to markers": "Convert segments to markers",
-  "Convert subtitiles into segments": "Convert subtitiles into segments",
+  "Convert subtitiles into segments": "Convert subtitles into segments",
   "Convert to supported format": "Convert to supported format",
   "Converting to supported format": "Converting to supported format",
   "Copy": "Copy",