Add missing space in the description of Toggle::DisallowSpirv

BUG=chromium:1214923

Change-Id: Iac9dce87c86c38175f9081de9fc8611a3b0040f5
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/84800
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/dawn/native/Toggles.cpp b/src/dawn/native/Toggles.cpp
index e36c671..b3bdd10 100644
--- a/src/dawn/native/Toggles.cpp
+++ b/src/dawn/native/Toggles.cpp
@@ -188,8 +188,8 @@
               "https://crbug.com/dawn/776"}},
             {Toggle::DisallowSpirv,
              {"disallow_spirv",
-              "Disallow usage of SPIR-V completely so that only WGSL is used for shader modules."
-              "This is useful to prevent a Chromium renderer process from successfully sending"
+              "Disallow usage of SPIR-V completely so that only WGSL is used for shader modules. "
+              "This is useful to prevent a Chromium renderer process from successfully sending "
               "SPIR-V code to be compiled in the GPU process.",
               "https://crbug.com/1214923"}},
             {Toggle::DumpShaders,