[gdb/doc] Fix gdb.unwinder docs

When building gdb with an older makeinfo (4.13), I run into:
...
gdb/doc/python.texi:3015: warning: `(' follows defined name \
  `gdb.unwinder.Unwinder.__init__' instead of whitespace.
gdb/doc/python.texi:3041: warning: `(' follows defined name \
  `gdb.unwinder.FrameId.__init__' instead of whitespace.
...

The warnings are related to these two lines:
...
@defun gdb.unwinder.Unwinder.__init__(name)
  ...
@defun gdb.unwinder.FrameId.__init__(sp, pc, special = @code{None})
...

Indeed, when checking the command and variable index, we can see that it
contains an incorrect entry:
...
  gdb.unwinder.FrameId.__init__(sp,:          Unwinding Frames in Python
...

Fix this by adding a space before the left parenthesis.

Tested by rebuilding the documentation and checking the command and variable
index.

1 files changed, 2 insertions, 2 deletions

diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index d66cae6..6087b08 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -3014,7 +3014,7 @@ unwinders can derive, though it is not required that unwinders derive
 from this class, so long as any user created unwinder has the required
 @code{name} and @code{enabled} attributes.
 
-@defun gdb.unwinder.Unwinder.__init__(name)
+@defun gdb.unwinder.Unwinder.__init__ (name)
 The @var{name} is a string used to reference this unwinder within some
 @value{GDBN} commands (@pxref{Managing Registered Unwinders}).
 @end defun
@@ -3040,7 +3040,7 @@ most cases this class will be sufficient.
 
 @code{gdb.unwinder.FrameId} has the following method:
 
-@defun gdb.unwinder.FrameId.__init__(sp, pc, special = @code{None})
+@defun gdb.unwinder.FrameId.__init__ (sp, pc, special = @code{None})
 The @var{sp} and @var{pc} arguments are required and should be either
 a @code{gdb.Value} object, or an integer.