Everywhere: Replace a bundle of dbg with dbgln.

These changes are arbitrarily divided into multiple commits to make it
easier to find potentially introduced bugs with git bisect.Everything:

The modifications in this commit were automatically made using the
following command:

    find . -name '*.cpp' -exec sed -i -E 's/dbg\(\) << ("[^"{]*");/dbgln\(\1\);/' {} \;

Kernel/FileSystem/DevFS.cpp

@@ -302,7 +302,7 @@ KResultOr<NonnullRefPtr<Inode>> DevFSRootDirectoryInode::create_child(const Stri
             if (link.name() == name)
                 return KResult(-EEXIST);
         }
-        dbg() << "DevFS: Success on create new symlink";
+        dbgln("DevFS: Success on create new symlink");
         auto new_link_inode = adopt(*new DevFSLinkInode(m_parent_fs, name));
         m_links.append(new_link_inode);
         m_parent_fs.m_nodes.append(new_link_inode);

Kernel/FileSystem/Ext2FileSystem.cpp

@@ -215,7 +215,7 @@ Ext2FS::BlockListShape Ext2FS::compute_block_list_shape(unsigned blocks) const
     if (!blocks_remaining)
         return shape;
 
-    dbg() << "we don't know how to compute tind ext2fs blocks yet!";
+    dbgln("we don't know how to compute tind ext2fs blocks yet!");
     ASSERT_NOT_REACHED();
 
     shape.triply_indirect_blocks = min(blocks_remaining, entries_per_block * entries_per_block * entries_per_block);
@@ -420,7 +420,7 @@ bool Ext2FS::write_block_list_for_inode(InodeIndex inode_index, ext2_inode& e2in
         return true;
 
     // FIXME: Implement!
-    dbg() << "we don't know how to write tind ext2fs blocks yet!";
+    dbgln("we don't know how to write tind ext2fs blocks yet!");
     ASSERT_NOT_REACHED();
 }
 
@@ -1137,7 +1137,7 @@ Vector<Ext2FS::BlockIndex> Ext2FS::allocate_blocks(GroupIndex preferred_group_in
 
     Vector<BlockIndex> blocks;
 #ifdef EXT2_DEBUG
-    dbg() << "Ext2FS: allocate_blocks:";
+    dbgln("Ext2FS: allocate_blocks:");
 #endif
     blocks.ensure_capacity(count);
 
@@ -1474,7 +1474,7 @@ KResultOr<NonnullRefPtr<Inode>> Ext2FS::create_inode(InodeIdentifier parent_id,
 
     size_t needed_blocks = ceil_div(static_cast<size_t>(size), block_size());
     if ((size_t)needed_blocks > super_block().s_free_blocks_count) {
-        dbg() << "Ext2FS: create_inode: not enough free blocks";
+        dbgln("Ext2FS: create_inode: not enough free blocks");
         return KResult(-ENOSPC);
     }
 

Kernel/FileSystem/Plan9FileSystem.cpp

@@ -246,7 +246,7 @@ bool Plan9FS::initialize()
 
     result = post_message_and_wait_for_a_reply(attach_message);
     if (result.is_error()) {
-        dbg() << "Attaching failed";
+        dbgln("Attaching failed");
         return false;
     }
 
@@ -663,7 +663,7 @@ ssize_t Plan9FS::adjust_buffer_size(ssize_t size) const
 
 void Plan9FS::thread_main()
 {
-    dbg() << "Plan9FS: Thread running";
+    dbgln("Plan9FS: Thread running");
     do {
         auto result = read_and_dispatch_one_message();
         if (result.is_error()) {
@@ -676,11 +676,11 @@ void Plan9FS::thread_main()
             }
             m_completions.clear();
             m_completion_blocker.unblock_all();
-            dbg() << "Plan9FS: Thread terminating, error reading";
+            dbgln("Plan9FS: Thread terminating, error reading");
             return;
         }
     } while (!m_thread_shutdown);
-    dbg() << "Plan9FS: Thread terminating";
+    dbgln("Plan9FS: Thread terminating");
 }
 
 void Plan9FS::ensure_thread()

Kernel/FileSystem/ProcFS.cpp

@@ -1296,7 +1296,7 @@ ssize_t ProcFSInode::read_bytes(off_t offset, ssize_t count, UserOrKernelBuffer&
         return -EIO;
     if (!description->data()) {
 #ifdef PROCFS_DEBUG
-        dbg() << "ProcFS: Do not have cached data!";
+        dbgln("ProcFS: Do not have cached data!");
 #endif
         return -EIO;
     }

Kernel/FileSystem/VirtualFileSystem.cpp

@@ -119,7 +119,7 @@ KResult VFS::unmount(Inode& guest_inode)
         if (&mount.guest() == &guest_inode) {
             auto result = mount.guest_fs().prepare_to_unmount();
             if (result.is_error()) {
-                dbg() << "VFS: Failed to unmount!";
+                dbgln("VFS: Failed to unmount!");
                 return result;
             }
             dbg() << "VFS: found fs " << mount.guest_fs().fsid() << " at mount index " << i << "! Unmounting...";