Remove obsolete "known problem" from Windows instructions

Also clarify a bit that it's not interfacing with other Windows
libraries that is possible with the MSVC toolchain, but only with ones
that are incompatible with MINGW. Which are not that many after all.

And add a comment that using the MSVC toolchain allows using the Visual
Studio debugger.

Author: sdroege

docs-src/requirements.md

@@ -30,8 +30,9 @@ The __gtk__ crate expects __GTK+__, __GLib__ and __Cairo__ development files to
 ## Windows
 
 On Windows Rust can use either the MSVC toolchain or the GNU toolchain. The latter is easier to
-install, but the former provides a better overall experience and allows interfacing with other
-Windows libraries.
+install, but the former provides a better overall experience and allows interfacing with Windows
+libraries that are incompatible with the GNU toolchain and for example usage
+of the Visual Studio debugger.
 
 ### MSVC toolchain
 
@@ -56,12 +57,6 @@ gtk-theme-name=win32
 
 #### Possible problems
 
-##### `unresolved external symbol gtk_font_chooser_level_get_type`
-
-This is [a bug](https://github.com/gtk-rs/gtk/issues/794) in version 0.6 of gtk-rs with versions of
-GTK prior to 3.22.30; either use gtk-rs from Git directly or backport [the fix](https://github.com/gtk-rs/gtk/pull/804)
-into the copy of gtk-rs in your Cargo registry.
-
 ##### `process didn't exit successfully (exit code: 0xc0000139, STATUS_ENTRYPOINT_NOT_FOUND)`
 
 `%VCPKGDIR%\bin` is too late in the `PATH` environment variable, and DLLs for other programs are being found before the ones installed alongside GTK.  Move `%VCPKGDIR%\bin` earlier in your `PATH` and try again.