Eliminating doxygen warnings by fixing the documentation

* Fix "end of file while inside a group" doxygen warnings.

* Fix "unknown command" doxygen warnings caused by incorrect
  argument references. Instead of `@foo`, `@a foo` is the proper
  format.

* Fix "unknown command" doxygen warnings caused by incorrect
  parameter direction specifications. Instead of `@in`, `@out`,
  and `@in-out`, `[in]`, `[out]`, and `[in,out]` are the proper
  formats.

* Wrapping special characters in quotes to avoid doxygen
  confusion. Raw pipe, semicolon, dot, backslash, etc. characters
  can drive doxygen into various misinterpretations and warnings.
  E.g.:
  ```
  End of list marker found without any preceding list items
  Found unknown command
  ```
  Putting quotes around such text snipets eliminates the errors.

* Fix the documentation of `ecma_builtin_global_object_print`. Raw
  <> and \ sequences confused doxygen in various ways (it tried to
  interpret them as XML tags and doxygen commands).

* Fix "ignoring title that does not match old title" doxygen
  warnings. At some places, the group titles were out of sync, at
  others, the group names were incorrect.

* Fix "parameters are not documented" doxygen warnings. Fixing
  various typos in the inline parameter documentations (`/*`,
  `/**`, `/** <`, and `/**>` are all considered incorrect, the
  right format is `/**<`).

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu

jerry-libc/jerry-libc.c

@@ -54,7 +54,7 @@ CALL_PRAGMA (GCC optimize ("-fno-tree-loop-distribute-patterns"))
 /**
  * memset
  *
- * @return @s
+ * @return @a s
  */
 void * __attr_used___ // FIXME
 memset (void *s,  /**< area to set values in */