FILE: fix/add doxygen comments

src/file.c

@@ -21,7 +21,7 @@
 
 /**
  * @file file.c
- * Allows operations of files, such as reading
+ * Allows operations on files, such as reading
  * and writing.
  * @brief file operations
  */

src/file.h

@@ -42,6 +42,13 @@
 string *
 read_file(char const * const filename);
 
+/**
+ * Write a string to a file. The file will be pruned or created
+ * if it does not exist.
+ *
+ * @param wstring the string to write to the file
+ * @param filename the name of the file to write to
+ */
 void
 write_file(string const *wstring, char const * const filename);