Refactor Paper Tonic Modern colorscheme and enhance semantic highlighting

- Updated highlights.scm to improve CSS, HTML, and data attribute captures with higher priority.
- Added a new Lua function to display highlight group and color information under the cursor.
- Expanded editor, semantic, syntax, and TreeSitter highlight groups for better visual consistency across languages.
- Created test files for PHP, HTML, CSS, and Lua to validate syntax highlighting.
- Implemented a shell script to test semantic highlights in a Neovim session.
- Simplified colorscheme loading process by removing unnecessary plugin specifications.

test-colorscheme.lua

@@ -0,0 +1,38 @@
+-- Test file for Paper Tonic Modern colorscheme
+-- This file tests various syntax highlighting
+
+-- Comments should be light gray, italic, bold
+local function test_function()
+  -- Strings should be dark gray
+  local my_string = "Hello, world!"
+  
+  -- Numbers and booleans
+  local my_number = 42
+  local my_bool = true
+  
+  -- Keywords and conditionals
+  if my_bool then
+    print(my_string)
+  end
+  
+  -- Loops
+  for i = 1, 10 do
+    print(i)
+  end
+  
+  return my_number
+end
+
+-- Test HTML colors (should be blue - c3)
+local html = [[
+  <div class="test">
+    <p>Hello</p>
+  </div>
+]]
+
+-- Test CSS colors (should be green - c2)
+local css = [[
+  .test {
+    color: red;
+  }
+]]