client/Client: pass std::string_view to Write()

Almost all callers have string literal, and the length is known at
compile time.

src/client/Client.hxx

@@ -150,7 +150,9 @@ public:
 	/**
 	 * Write a null-terminated string.
 	 */
-	bool Write(const char *data) noexcept;
+	bool Write(std::string_view s) noexcept {
+		return Write(s.data(), s.size());
+	}
 
 	/**
 	 * returns the uid of the client process, or a negative value

src/client/Write.cxx

@@ -27,9 +27,3 @@ Client::Write(const void *data, size_t length) noexcept
 	/* if the client is going to be closed, do nothing */
 	return !IsExpired() && FullyBufferedSocket::Write(data, length);
 }
-
-bool
-Client::Write(const char *data) noexcept
-{
-	return Write(data, strlen(data));
-}