doc: use category name for @defvar

src/doc/new-doc/developer-guide/contributing-documentation.txi

@@ -116,7 +116,7 @@ description
 @defvrx {Constant} MOST_POSITIVE_FIXNUM
 These constants mark the limits of a fixnum.
 @end defvr
-@defvr {FFI} *use-dffi*
+@defvr Variable {ffi:*use-dffi*}
 Description.
 @end defvr
 @end verbatim

src/doc/new-doc/extensions/ffi_dffi.txi

@@ -3,7 +3,7 @@
 @cindex Dynamic foreign function interface
 
 @lspindex ffi:*use-dffi*
-@defvr {FFI} {*use-dffi*}
+@defvr Variable {ffi:*use-dffi*}
 This variable controls whether @code{DFFI} is used or not.
 @end defvr
 

src/doc/new-doc/extensions/ffi_uffi.txi

@@ -676,7 +676,7 @@ The boolean flag.
 @end defun
 
 @lspindex ffi:+null-cstring-pointer+
-@defvr {FFI} {+null-cstring-pointer+}
+@defvr Variable {ffi:+null-cstring-pointer+}
 A NULL cstring pointer. This can be used for testing if a cstring
 returned by a function is NULL.
 @end defvr

src/doc/new-doc/extensions/mp_ref_process.txi

@@ -275,7 +275,7 @@ Example:
 @deftypefun cl_object mp_current_process ()
 @end deftypefun
 
-@defvr {mp} {*current-process*}
+@defvr Variable {mp:*current-process*}
 Returns/holds the current process of a caller.
 @end defvr
 

src/doc/new-doc/standards/data_and_control_flow.txi

@@ -114,7 +114,7 @@ defined functions, you should issue @code{(setq si:*keep-definitions*
 t)} at the beginning of your session.
 
 @lspindex si:*keep-definitions*
-@defvr {SI} {*keep-definitions*}
+@defvr Variable {si:*keep-definitions*}
 If set to @code{T} ECL will preserve the compiled function source code
 for disassembly and recompilation.
 @end defvr