Update mandoc style sheet

src/asm/rgbasm.1

@@ -153,7 +153,9 @@ prefix, entries are listed alphabetically.
 Warns when
 .Ic WARN Ns No -type
 assertions fail. (See
-.Xr rgbasm 5 "Aborting the assembly process"
+.Dq Aborting the assembly process
+in
+.Xr rgbasm 5
 for
 .Ic ASSERT ) .
 .It Fl Wbuiltin-args
@@ -187,24 +189,31 @@ section type are encountered.
 This warning is enabled by
 .Fl Wextra .
 .It Fl Wshift
-Warn when shifting triggers C undefined behavior, potentially causing unpredictable behavior.
-Shfting behavior will be changed and this warning removed before next release.
+Warn when shifting right a negative value.
+Use a division by 2^N instead.
+.It Fl Wshift-amount
+Warn when a shift's operand is negative or greater than 32.
+.It Fl Wno-truncation
+Warn when an implicit truncation (for example,
+.Ic db )
+loses some bits.
 .It Fl Wno-user
-Warns when the
+Warn when the
 .Ic WARN
 built-in is executed. (See
-.Xr rgbasm 5 "Aborting the assembly process"
+.Dq Aborting the assembly process
+in
+.Xr rgbasm 5
 for
 .Ic WARN ) .
 .El
 .Sh EXAMPLES
 You can assemble a source file in two ways.
-Straightforward way:
 .Pp
+Straightforward way:
 .Dl $ rgbasm -o bar.o foo.asm
 .Pp
 Pipes way:
-.Pp
 .Dl $ cat foo.asm | rgbasm -o bar.o -
 .Dl $ rgbasm -o bar.o - < foo.asm
 .Pp