[typing] add location to warning message

src/plugins/e-acsl/tests/bts/oracle/bts1307.res.oracle

-[kernel] tests/bts/bts1307.i:14: Warning: 
-  Floating-point constant 0.4 is not represented exactly. Will use 0x1.999999999999ap-2. See documentation for option -warn-decimal-float
+[kernel:parser:decimal-float] tests/bts/bts1307.i:14: Warning: 
+  Floating-point constant 0.4 is not represented exactly. Will use 0x1.999999999999ap-2.
+  (warn-once: no further messages from category 'parser:decimal-float' will be emitted)
 [e-acsl] beginning translation.
 [e-acsl] tests/bts/bts1307.i:23: Warning: approximating a real number by a float
 [e-acsl] tests/bts/bts1307.i:23: Warning: 

src/plugins/e-acsl/tests/format/oracle/printf.res.oracle

-[kernel] tests/format/printf.c:88: Warning: 
-  Floating-point constant 0.2 is not represented exactly. Will use 0x1.999999999999ap-3. See documentation for option -warn-decimal-float
+[kernel:parser:decimal-float] tests/format/printf.c:88: Warning: 
+  Floating-point constant 0.2 is not represented exactly. Will use 0x1.999999999999ap-3.
+  (warn-once: no further messages from category 'parser:decimal-float' will be emitted)
 [e-acsl] beginning translation.
 [e-acsl] Warning: annotating undefined function `abort':
   the generated program may miss memory instrumentation