VAX/doc: Fix issues with FP format option documentation

Use the correct names of the D_floating and G_floating data formats as
per the VAX ISA nomenclature[1].  Document the `-md', `-md-float', and
`-mg-float' options.

References:

[1] DEC STD 032-0 "VAX Architecture Standard", Digital Equipment
    Corporation, A-DS-EL-00032-00-0 Rev J, December 15, 1989, Section
    1.2 "Data Types", pp. 1-7, 1-9

	gcc/
	* doc/invoke.texi (Option Summary): Add `-md', `-md-float', and
	`-mg-float' options.  Reorder, matching VAX Options.
	(VAX Options): Reword the description of `-mg' option.  Add
	`-md', `-md-float', and `-mg-float' options.

1 files changed, 12 insertions, 2 deletions

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index c9d8f6b..2cba380 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -1429,7 +1429,7 @@ See RS/6000 and PowerPC Options.
 -mbig-switch}
 
 @emph{VAX Options}
-@gccoptlist{-mg  -mgnu  -munix  -mlra}
+@gccoptlist{-munix  -mgnu  -md  -md-float  -mg  -mg-float  -mlra}
 
 @emph{Visium Options}
 @gccoptlist{-mdebug  -msim  -mfpu  -mno-fpu  -mhard-float  -msoft-float
@@ -34129,9 +34129,19 @@ ranges.
 Do output those jump instructions, on the assumption that the
 GNU assembler is being used.
 
+@opindex md
+@opindex md-float
+@item -md
+@itemx -md-float
+Use the D_floating data format for double-precision floating-point numbers
+instead of G_floating.
+
 @opindex mg
+@opindex mg-float
 @item -mg
-Output code for G-format floating-point numbers instead of D-format.
+@itemx -mg-float
+Use the G_floating data format for double-precision floating-point numbers
+instead of D_floating.
 
 @opindex mlra
 @opindex mno-lra