add reason fixes to section 1.4

Author: jakubsvec001

src/content/1.4/code/ocaml/snippet04.ml

@@ -1,4 +1,4 @@
 let ( >=> ) = fun m1 m2 ->
   let y, s1 = m1 x in
   let z, s2 = m2 x in
-    z, StringLabels.concat +sep:"" [ s1; s2 ]
+    z, StringLabels.concat ~sep:"" [ s1; s2 ]

src/content/1.4/code/reason/snippet04.re

@@ -1 +1,7 @@
-let pure = x => (x, "");
+let (>=>) = (m1, m2) => {
+  let (y, s1) = m1(x);
+
+  let (z, s2) = m2(x);
+
+  (z, StringLabels.concat(~sep="", [s1, s2]));
+};

src/content/1.4/code/reason/snippet05.re

@@ -1,2 +1 @@
-let up_case: string => writer(string) =
-  s => (String.uppercase(s), "up_case ");
+let return: 'a => writer('a) = a => (a, "");

src/content/1.4/code/reason/snippet06.re

@@ -1,4 +1,5 @@
-let to_words: string => writer(list(string)) = (
-  s => (String.split(s, ~on=' '), "to_words "):
-    string => writer(list(string))
-);
+let up_case: string => writer(string) =
+  s => (String.uppercase(s), "up_case ");
+
+let to_words: string => writer(list(string)) =
+  s => (String.split(s, ~on=' '), "to_words ");kkkk