[Clang] Fixes a diagnostic typo.

[Mordante]

Summary

Some small style updates as drive-by.

[ChuanqiXu]

Thanks!

clang/include/clang/Basic/DiagnosticSerializationKinds.td

def warn_module_system_bit_conflict : Warning<
   InGroup<ModuleConflict>;
 
 def warn_eagerly_load_for_standard_cplusplus_modules : Warning<
   "the form '-fmodule-file=<BMI-path>' is deprecated for standard C++ named modules;"
   "consider to use '-fmodule-file=<module-name>=<BMI-path>' instead">,
   InGroup<DiagGroup<"eager-load-cxx-named-modules">>;
 
 def warn_reading_std_cxx_module_by_implicit_paths : Warning<
-  "it is deprecated to read module '%0' implcitly; it is going to be removed in clang18; "
+  "it is deprecated to read module '%0' implicitly; it is going to be removed in clang 18; "
   "consider to specify the dependencies explicitly">,
   InGroup<DiagGroup<"read-modules-implicitly">>;
 } // let CategoryName
 
 let CategoryName = "AST Serialization Issue" in {
 def warn_module_uses_date_time : Warning<
   "%select{precompiled header|module}0 uses __DATE__ or __TIME__">,
   InGroup<DiagGroup<"pch-date-time">>;
 def err_module_no_size_mtime_for_header : Error<
   "cannot emit module %0: %select{size|mtime}1 must be explicitly specified "
   "for missing header file \"%2\"">;
 def err_module_unable_to_hash_content : Error<
   "failed to hash content for '%0' because memory buffer cannot be retrieved">;
 } // let CategoryName
 } // let Component
 

clang/test/Modules/no-implicit-std-cxx-module.cppm

 // RUN: rm -rf %t
 // RUN: split-file %s %t
 // RUN: cd %t
 //
 // RUN: %clang_cc1 -std=c++20 -emit-module-interface %t/b.cppm -o %t/b.pcm
 // RUN: %clang_cc1 -std=c++20 -emit-module-interface %t/a.cppm -fmodule-file=b=%t/b.pcm \
 // RUN:     -o %t/a.pcm
 // RUN: %clang_cc1 -std=c++20 %t/user.cpp -fmodule-file=a=%t/a.pcm -verify -fsyntax-only
 // RUN: %clang_cc1 -std=c++20 %t/user.cpp -fmodule-file=a=%t/a.pcm -verify -fsyntax-only \
-// RUN:     -Wno-read-modules-implicitly -DNO_DIAG 
+// RUN:     -Wno-read-modules-implicitly -DNO_DIAG
 // RUN: %clang_cc1 -std=c++20 %t/user.cpp -fmodule-file=a=%t/a.pcm -fmodule-file=b=%t/b.pcm \
 // RUN:     -DNO_DIAG -verify -fsyntax-only
 //
 // RUN: %clang_cc1 -std=c++20 %t/a.pcm -S -emit-llvm -o - 2>&1 | FileCheck %t/a.cppm
 // RUN: %clang_cc1 -std=c++20 %t/a.pcm -fmodule-file=b=%t/b.pcm -S -emit-llvm -o - 2>&1 \
 // RUN:     | FileCheck %t/a.cppm -check-prefix=CHECK-CORRECT
 //
 // RUN: mkdir -p %t/tmp

 
 //--- a.cppm
 export module a;
 import b;
 export int a() {
     return b() + 43;
 }
 
-// CHECK: it is deprecated to read module 'b' implcitly;
+// CHECK: it is deprecated to read module 'b' implicitly;
 
 // CHECK-CORRECT-NOT: warning
 // CHECK-CORRECT-NOT: error
 
 // CHECK-ERROR: error: module file{{.*}}not found: module file not found
 
 
 //--- user.cpp
 #ifdef NO_DIAG
 // expected-no-diagnostics
 #else
- // expected-warning@+2 {{it is deprecated to read module 'b' implcitly;}}
+ // expected-warning@+2 {{it is deprecated to read module 'b' implicitly;}}
 #endif
 import a;
 int use() {
     return a();
-}
+}