include/ruby/internal/xmalloc.h: document rb_eNoMemError

It was my bad, the exception that actually raises is rb_eNoMemError.
[ci skip]

include/ruby/internal/xmalloc.h

@@ -62,7 +62,7 @@ RBIMPL_ATTR_ALLOC_SIZE((1))
  *   - In case of `ENOMEM` it tries to GC to make some room.
  *
  * @param[in]  size            Requested amount of memory.
- * @exception  rb_eMemError  No space left for `size` bytes allocation.
+ * @exception  rb_eNoMemError  No space left for `size` bytes allocation.
  * @return     A valid pointer  to an allocated storage instance;  which has at
  *             least `size` bytes width, with appropriate alignment detected by
  *             the underlying malloc() routine.
@@ -91,7 +91,7 @@ RBIMPL_ATTR_ALLOC_SIZE((1,2))
  *
  * @param[in]  nelems          Number of elements.
  * @param[in]  elemsiz         Size of an element.
- * @exception  rb_eMemError  No space left for allocation.
+ * @exception  rb_eNoMemError  No space left for allocation.
  * @exception  rb_eArgError    `nelems` * `elemsiz` would overflow.
  * @return     A valid pointer  to an allocated storage instance;  which has at
  *             least  `nelems`  *  `elemsiz`   bytes  width,  with  appropriate
@@ -120,7 +120,7 @@ RBIMPL_ATTR_ALLOC_SIZE((1,2))
  *
  * @param[in]  nelems          Number of elements.
  * @param[in]  elemsiz         Size of an element.
- * @exception  rb_eMemError  No space left for allocation.
+ * @exception  rb_eNoMemError  No space left for allocation.
  * @exception  rb_eArgError    `nelems` * `elemsiz` would overflow.
  * @return     A valid pointer  to an allocated storage instance;  which has at
  *             least  `nelems`  *  `elemsiz`   bytes  width,  with  appropriate
@@ -146,19 +146,19 @@ RBIMPL_ATTR_ALLOC_SIZE((2))
  *
  * @param[in]  ptr             A valid  pointer to a storage  instance that was
  *                             previously returned  from either ruby_xmalloc(),
- *                           ruby_xmalloc2(),  ruby_xcalloc(), ruby_xrealloc(),
- *                           or ruby_xrealloc2().
+ *                             ruby_xmalloc2(),                 ruby_xcalloc(),
+ *                             ruby_xrealloc(), or ruby_xrealloc2().
  * @param[in]  newsiz          Requested new amount of memory.
- * @exception  rb_eMemError  No space left for `newsiz` bytes allocation.
+ * @exception  rb_eNoMemError  No space left for `newsiz` bytes allocation.
  * @retval     ptr             In case the function  returns the passed pointer
- *                           as-is, the storage instance that the pointer holds
- *                           is  either  grown or  shrunken  to  have at  least
- *                           `newsiz` bytes.
+ *                             as-is,  the storage  instance  that the  pointer
+ *                             holds  is either  grown or  shrunken to  have at
+ *                             least `newsiz` bytes.
  * @retval     otherwise       A  valid pointer  to a  newly allocated  storage
- *                           instance which has at  least `newsiz` bytes width,
- *                           and  holds previous  contents of  `ptr`.  In  this
- *                           case `ptr` is  invalidated as if it  was passed to
- *                           ruby_xfree().
+ *                             instance  which  has  at  least  `newsiz`  bytes
+ *                             width, and holds previous contents of `ptr`.  In
+ *                             this  case `ptr`  is  invalidated as  if it  was
+ *                             passed to ruby_xfree().
  * @note       It doesn't return NULL.
  * @warning    Unlike some realloc() implementations, passing zero to `elemsiz`
  *             is not the  same as calling ruby_xfree(),  because this function
@@ -194,21 +194,22 @@ RBIMPL_ATTR_ALLOC_SIZE((2,3))
  *
  * @param[in]  ptr             A valid  pointer to a storage  instance that was
  *                             previously returned  from either ruby_xmalloc(),
- *                           ruby_xmalloc2(),  ruby_xcalloc(), ruby_xrealloc(),
- *                           or ruby_xrealloc2().
+ *                             ruby_xmalloc2(),                 ruby_xcalloc(),
+ *                             ruby_xrealloc(), or ruby_xrealloc2().
+
  * @param[in]  newelems        Requested new number of elements.
  * @param[in]  newsiz          Requested new size of each element.
- * @exception  rb_eMemError  No space left for  allocation.
+ * @exception  rb_eNoMemError  No space left for  allocation.
  * @exception  rb_eArgError    `newelems` * `newsiz` would overflow.
  * @retval     ptr             In case the function  returns the passed pointer
- *                           as-is, the storage instance that the pointer holds
- *                           is  either  grown or  shrunken  to  have at  least
- *                           `newelems` * `newsiz` bytes.
+ *                             as-is,  the storage  instance  that the  pointer
+ *                             holds  is either  grown or  shrunken to  have at
+ *                             least `newelems` * `newsiz` bytes.
  * @retval     otherwise       A  valid pointer  to a  newly allocated  storage
- *                           instance which has at  least `newelems` * `newsiz`
- *                           bytes width, and holds previous contents of `ptr`.
- *                           In this  case `ptr`  is invalidated  as if  it was
- *                           passed to ruby_xfree().
+ *                             instance  which   has  at  least   `newelems`  *
+ *                             `newsiz`   bytes  width,   and  holds   previous
+ *                             contents  of  `ptr`.   In  this  case  `ptr`  is
+ *                             invalidated as if it was passed to ruby_xfree().
  * @note       It doesn't return NULL.
  * @warning    Unlike some  realloc() implementations,  passing zero  to either
  *             `newelems`   or  `elemsiz`   are   not  the   same  as   calling