[gdb] Fix trailing whitespace in annotate.texinfo

Fix:
...
gdb/doc/annotate.texinfo:127: trailing whitespace.
+(gdb)
gdb/doc/annotate.texinfo:132: trailing whitespace.
+$
gdb/doc/annotate.texinfo:732: trailing whitespace.
+@code{step} or @code{continue},
gdb/doc/annotate.texinfo:738: trailing whitespace.
+is output.  When the program stops,
...

Verified by checking annotate.html.

Approved-By: Tom Tromey <tom@tromey.com>

gdb/contrib/check-whitespace-pre-commit.py

@@ -23,7 +23,6 @@ re_ignore = re.compile("ChangeLog")
 
 # Files that are not clean, so they're only checked when changes.
 todo_list = [
-    "gdb/doc/annotate.texinfo",
     "gdb/doc/refcard.tex",
 ]
 

gdb/doc/annotate.texinfo

@@ -124,12 +124,12 @@ for details.
 This GDB was configured as "sparc-sun-sunos4.1.3"
 
 ^Z^Zpre-prompt
-(gdb) 
+(gdb)@w{ }
 ^Z^Zprompt
 quit
 
 ^Z^Zpost-prompt
-$ 
+$@w{ }
 @end smallexample
 
 Here @samp{quit} is input to @value{GDBN}; the rest is output from
@@ -729,13 +729,13 @@ deleted a breakpoint.
 @findex starting
 @findex stopping
 When the program starts executing due to a @value{GDBN} command such as
-@code{step} or @code{continue}, 
+@code{step} or @code{continue},
 
 @smallexample
 ^Z^Zstarting
 @end smallexample
 
-is output.  When the program stops, 
+is output.  When the program stops,
 
 @smallexample
 ^Z^Zstopped