Rename files to use abbreviations (#3389)

Reflects these recent PRs:
* #3375 
* #3382

toolchain/check/BUILD

@@ -34,7 +34,7 @@ cc_library(
         "check.cpp",
         "context.cpp",
         "convert.cpp",
-        "declaration_name_stack.cpp",
+        "decl_name_stack.cpp",
         "inst_block_stack.cpp",
         "return.cpp",
         "return.h",
@@ -47,7 +47,7 @@ cc_library(
         "check.h",
         "context.h",
         "convert.h",
-        "declaration_name_stack.h",
+        "decl_name_stack.h",
         "inst_block_stack.h",
         "pending_block.h",
     ],

toolchain/check/context.cpp

@@ -10,7 +10,7 @@
 #include "common/check.h"
 #include "common/vlog.h"
 #include "llvm/ADT/Sequence.h"
-#include "toolchain/check/declaration_name_stack.h"
+#include "toolchain/check/decl_name_stack.h"
 #include "toolchain/check/inst_block_stack.h"
 #include "toolchain/lex/tokenized_buffer.h"
 #include "toolchain/parse/node_kind.h"

toolchain/check/context.h

@@ -9,7 +9,7 @@
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/ADT/SmallVector.h"
-#include "toolchain/check/declaration_name_stack.h"
+#include "toolchain/check/decl_name_stack.h"
 #include "toolchain/check/inst_block_stack.h"
 #include "toolchain/check/node_stack.h"
 #include "toolchain/parse/tree.h"

toolchain/check/decl_name_stack.cpp

@@ -2,7 +2,7 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-#include "toolchain/check/declaration_name_stack.h"
+#include "toolchain/check/decl_name_stack.h"
 
 #include "toolchain/check/context.h"
 

toolchain/check/decl_name_stack.h

@@ -2,8 +2,8 @@
 // Exceptions. See /LICENSE for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-#ifndef CARBON_TOOLCHAIN_CHECK_DECLARATION_NAME_STACK_H_
-#define CARBON_TOOLCHAIN_CHECK_DECLARATION_NAME_STACK_H_
+#ifndef CARBON_TOOLCHAIN_CHECK_DECL_NAME_STACK_H_
+#define CARBON_TOOLCHAIN_CHECK_DECL_NAME_STACK_H_
 
 #include "llvm/ADT/SmallVector.h"
 #include "toolchain/parse/tree.h"
@@ -198,4 +198,4 @@ class DeclNameStack {
 
 }  // namespace Carbon::Check
 
-#endif  // CARBON_TOOLCHAIN_CHECK_DECLARATION_NAME_STACK_H_
+#endif  // CARBON_TOOLCHAIN_CHECK_DECL_NAME_STACK_H_