add information and minor restructuring

src/if_else_while.md

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+# If, Else, While, Block
+
+Nimrod many different control flow constructs, including the standard `if`s, `else`s, and `while`s.
+
+``` Nimrod
+import strutils
+
+let
+  answer = 4  # Chosen by a fair dice roll,
+              # guaranteed to be random
+
+while true:
+  echo "I have a number from 1 to 10, what is it? "
+  let guess = parseInt(stdin.readLine)
+
+  if guess < answer:
+    echo "Too low, try again"
+  elif guess > answer:
+    echo "Too high, try again"
+  else:
+    echo "Correct!"
+    break
+```
+
+When inside a loop, it is possible to use `continue` or `break` any point within the loop with the standard semantics, where `continue` skips to the next iteration and `break` ends the loop.