tools: add msvc /P output to .gitignore

PR-URL: #35735
Reviewed-By: Michaël Zasso <targos@protonmail.com>

Author: gengjiawen

.gitignore

@@ -93,6 +93,9 @@ _UpgradeReport_Files/
 /*.host.mk
 /deps/openssl/openssl.target.mk
 /deps/zlib/zlib.target.mk
+# generated by MSVC with /P enabled
+tools/*/*.i
+tools/*/*.i.tmp
 
 # === Rules for release artifacts ===
 /*.tar.*