fix typos in switch descriptions (#17475)

diff --git a/shell/common/switches.h b/shell/common/switches.h
index e509b5c..abf1b3a 100644
--- a/shell/common/switches.h
+++ b/shell/common/switches.h
@@ -95,13 +95,13 @@
            "indefinitely however.")
 DEF_SWITCH(EnableSoftwareRendering,
            "enable-software-rendering",
-           "Enable rendering using the Skia software backend. This is useful"
-           "when testing Flutter on emulators. By default, Flutter will"
+           "Enable rendering using the Skia software backend. This is useful "
+           "when testing Flutter on emulators. By default, Flutter will "
            "attempt to either use OpenGL or Vulkan.")
 DEF_SWITCH(SkiaDeterministicRendering,
            "skia-deterministic-rendering",
-           "Skips the call to SkGraphics::Init(), thus avoiding swapping out"
-           "some Skia function pointers based on available CPU features. This"
+           "Skips the call to SkGraphics::Init(), thus avoiding swapping out "
+           "some Skia function pointers based on available CPU features. This "
            "is used to obtain 100% deterministic behavior in Skia rendering.")
 DEF_SWITCH(FlutterAssetsDir,
            "flutter-assets-dir",