added pretty_json.nim script

pretty_json.nim

@@ -0,0 +1,41 @@
+
+import strutils, json, os
+
+proc cleanupWhitespace(s: string): string =
+  ## Removes trailing whitespace and normalizes line endings to LF.
+  result = newStringOfCap(s.len)
+  var i = 0
+  while i < s.len:
+    if s[i] == ' ':
+      var j = i+1
+      while s[j] == ' ': inc j
+      if s[j] == '\c':
+        inc j
+        if s[j] == '\L': inc j
+        result.add '\L'
+        i = j
+      elif s[j] == '\L':
+        result.add '\L'
+        i = j+1
+      else:
+        result.add ' '
+        inc i
+    elif s[i] == '\c':
+      inc i
+      if s[i] == '\L': inc i
+      result.add '\L'
+    elif s[i] == '\L':
+      result.add '\L'
+      inc i
+    else:
+      result.add s[i]
+      inc i
+  if result[^1] != '\L':
+    result.add '\L'
+
+proc editJson() =
+  var contents = parseFile("packages.json")
+  doAssert contents.kind == JArray
+  writeFile("packages.json", contents.pretty.cleanupWhitespace)
+
+editJson()