Minor simplifications and doc for records

* doc/lispref/records.texi (Records): Mention size limit.
* etc/NEWS: Mention records.
* src/alloc.c (allocate_pseudovector, allocate_record):
Prefer 'PSEUDOVECTOR_SIZE_MASK' to its definiens.
(allocate_record): Check arg range here, not in callers, as this
simplifies the code.  Use allocate_vectorlike instead of
allocate_vector, to avoid duplicate runtime tests.
(Fmake_record, record): Don't mention PSEUDOVECTOR_SIZE_BITS in
the doc string, as it is not visible to the user.
(Fmake_record, record, Fcopy_record):
Prefer make_lisp_ptr to XSETVECTOR.
(record): Broaden memcpy to copy the type, too.

1 files changed, 4 insertions, 2 deletions

diff --git a/doc/lispref/records.texi b/doc/lispref/records.texi
index 9a5d900cfc9..a6c560cbcb9 100644
--- a/doc/lispref/records.texi
+++ b/doc/lispref/records.texi
@@ -14,8 +14,10 @@ instances.
 
   Internally, a record object is much like a vector; its slots can be
 accessed using @code{aref}.  However, the first slot is used to hold
-its type as returned by @code{type-of}.  Like arrays, records use
-zero-origin indexing: the first slot has index 0.
+its type as returned by @code{type-of}.  Also, in the current
+implementation records can have at most 4096 slots, whereas vectors
+can be much larger.  Like arrays, records use zero-origin indexing:
+the first slot has index 0.
 
   The printed representation of records is @samp{#s} followed by a
 list specifying the contents.  The first list element must be the