[clangd] Namespace style cleanup in cpp files. NFC.

Standardize on the most common namespace setup in our *.cpp files:
  using namespace llvm;
  namespace clang {
  namespace clangd {
  void foo(StringRef) { ... }
And remove redundant llvm:: qualifiers. (Except for cases like
make_unique where this causes problems with std:: and ADL).

This choice is pretty arbitrary, but some broad consistency is nice.
This is going to conflict with everything. Sorry :-/

Squash the other configurations:

A)
  using namespace llvm;
  using namespace clang;
  using namespace clangd;
  void clangd::foo(StringRef);
This is in some of the older files. (It prevents accidentally defining a
new function instead of one in the header file, for what that's worth).

B)
  namespace clang {
  namespace clangd {
  void foo(llvm::StringRef) { ... }
This is fine, but in practice the using directive often gets added over time.

C)
  namespace clang {
  namespace clangd {
  using namespace llvm; // inside the namespace
This was pretty common, but is a bit misleading: name lookup preferrs
clang::clangd::foo > clang::foo > llvm:: foo (no matter where the using
directive is).

llvm-svn: 344850
diff --git a/clang-tools-extra/clangd/Protocol.cpp b/clang-tools-extra/clangd/Protocol.cpp
index 805225a..3622a43 100644
--- a/clang-tools-extra/clangd/Protocol.cpp
+++ b/clang-tools-extra/clangd/Protocol.cpp
@@ -21,14 +21,14 @@
 #include "llvm/Support/Path.h"
 #include "llvm/Support/raw_ostream.h"
 
+using namespace llvm;
 namespace clang {
 namespace clangd {
-using namespace llvm;
 
 char LSPError::ID;
 
 URIForFile::URIForFile(std::string AbsPath) {
-  assert(llvm::sys::path::is_absolute(AbsPath) && "the path is relative");
+  assert(sys::path::is_absolute(AbsPath) && "the path is relative");
   File = std::move(AbsPath);
 }
 
@@ -57,7 +57,7 @@
 
 json::Value toJSON(const URIForFile &U) { return U.uri(); }
 
-llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const URIForFile &U) {
+raw_ostream &operator<<(raw_ostream &OS, const URIForFile &U) {
   return OS << U.uri();
 }
 
@@ -82,7 +82,7 @@
   };
 }
 
-llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Position &P) {
+raw_ostream &operator<<(raw_ostream &OS, const Position &P) {
   return OS << P.line << ':' << P.character;
 }
 
@@ -98,7 +98,7 @@
   };
 }
 
-llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Range &R) {
+raw_ostream &operator<<(raw_ostream &OS, const Range &R) {
   return OS << R.start << '-' << R.end;
 }
 
@@ -109,7 +109,7 @@
   };
 }
 
-llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Location &L) {
+raw_ostream &operator<<(raw_ostream &OS, const Location &L) {
   return OS << L.range << '@' << L.uri;
 }
 
@@ -139,7 +139,7 @@
   };
 }
 
-llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const TextEdit &TE) {
+raw_ostream &operator<<(raw_ostream &OS, const TextEdit &TE) {
   OS << TE.range << " => \"";
   printEscapedString(TE.newText, OS);
   return OS << '"';
@@ -342,7 +342,7 @@
   return O && O.map("textDocument", R.textDocument);
 }
 
-llvm::json::Value toJSON(const Diagnostic &D) {
+json::Value toJSON(const Diagnostic &D) {
   json::Object Diag{
       {"range", D.range},
       {"severity", D.severity},
@@ -366,7 +366,7 @@
   return O && O.map("diagnostics", R.diagnostics);
 }
 
-llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Diagnostic &D) {
+raw_ostream &operator<<(raw_ostream &OS, const Diagnostic &D) {
   OS << D.range << " [";
   switch (D.severity) {
     case 1:
@@ -399,7 +399,7 @@
   return O && O.map("changes", R.changes);
 }
 
-const llvm::StringLiteral ExecuteCommandParams::CLANGD_APPLY_FIX_COMMAND =
+const StringLiteral ExecuteCommandParams::CLANGD_APPLY_FIX_COMMAND =
     "clangd.applyFix";
 bool fromJSON(const json::Value &Params, ExecuteCommandParams &R) {
   json::ObjectMapper O(Params);
@@ -423,8 +423,7 @@
   };
 }
 
-llvm::raw_ostream &operator<<(llvm::raw_ostream &O,
-                              const SymbolInformation &SI) {
+raw_ostream &operator<<(raw_ostream &O, const SymbolInformation &SI) {
   O << SI.containerName << "::" << SI.name << " - " << toJSON(SI);
   return O;
 }
@@ -441,9 +440,9 @@
   return std::move(Cmd);
 }
 
-const llvm::StringLiteral CodeAction::QUICKFIX_KIND = "quickfix";
+const StringLiteral CodeAction::QUICKFIX_KIND = "quickfix";
 
-llvm::json::Value toJSON(const CodeAction &CA) {
+json::Value toJSON(const CodeAction &CA) {
   auto CodeAction = json::Object{{"title", CA.title}};
   if (CA.kind)
     CodeAction["kind"] = *CA.kind;
@@ -575,7 +574,7 @@
   return std::move(Result);
 }
 
-llvm::raw_ostream &operator<<(llvm::raw_ostream &O, const CompletionItem &I) {
+raw_ostream &operator<<(raw_ostream &O, const CompletionItem &I) {
   O << I.label << " - " << toJSON(I);
   return O;
 }
@@ -611,8 +610,7 @@
   return std::move(Result);
 }
 
-llvm::raw_ostream &operator<<(llvm::raw_ostream &O,
-                              const SignatureInformation &I) {
+raw_ostream &operator<<(raw_ostream &O, const SignatureInformation &I) {
   O << I.label << " - " << toJSON(I);
   return O;
 }
@@ -642,8 +640,7 @@
   };
 }
 
-llvm::raw_ostream &operator<<(llvm::raw_ostream &O,
-                              const DocumentHighlight &V) {
+raw_ostream &operator<<(raw_ostream &O, const DocumentHighlight &V) {
   O << V.range;
   if (V.kind == DocumentHighlightKind::Read)
     O << "(r)";
@@ -657,8 +654,7 @@
   return O && O.map("settings", CCP.settings);
 }
 
-bool fromJSON(const llvm::json::Value &Params,
-              ClangdCompileCommand &CDbUpdate) {
+bool fromJSON(const json::Value &Params, ClangdCompileCommand &CDbUpdate) {
   json::ObjectMapper O(Params);
   return O && O.map("workingDirectory", CDbUpdate.workingDirectory) &&
          O.map("compilationCommand", CDbUpdate.compilationCommand);