Outdated Installation Path for Modern gedit (v45+)

### Bug Report: Outdated Installation Instructions for gedit v45+

**Target Component:** Theme Installation Documentation / `README.md`

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#### **1. Summary of the Issue**
The current installation instructions direct users to place the theme XML file in `~/.local/share/gedit/styles/`. While this worked for older versions, it is **no longer compatible** with modern versions of gedit (v45 through the current v49) found on updated distributions like Fedora 43.

#### **2. Technical Background**
Starting with **gedit 45**, the application transitioned from using the standard GNOME `gtksourceview` library to a specialized fork called **`libgedit-gtksourceview`**. This architectural shift changed how the application scans for user-defined styles and syntax highlighting.

#### **3. Key Changes & Requirements**

* **New Directory Path:** gedit now looks for style schemes in a version-specific library directory.
* **Old Path:** `~/.local/share/gedit/styles/`
* **New Path:** `~/.local/share/libgedit-gtksourceview-300/styles/`
* **Metadata Requirement:** The `` tag must now include the `kind="dark"` (or `"light"`) attribute. Without this, gedit may fail to map the theme correctly to the system's global Dark Mode preference.
* **Removal of UI Installer:** The "Add Scheme" (`+`) button has been removed from the gedit Preferences menu. Manual file placement is currently the only reliable way to install custom themes.

#### **4. Steps to Reproduce**
1. Install gedit v45 or higher.
2. Follow current instructions to place the `.xml` file in `~/.local/share/gedit/styles/`.
3. Open gedit Preferences > Font & Colors.
4. **Result:** The theme is missing from the list.

#### **5. Suggested Documentation Update**
> **For gedit v45 and newer:**
> Copy the theme XML file to the following directory (create it if it does not exist):
> ```bash
> mkdir -p ~/.local/share/libgedit-gtksourceview-300/styles/
> cp your-theme.xml ~/.local/share/libgedit-gtksourceview-300/styles/
> ```
> Then, restart gedit to apply the changes.