Add glfwGetWindowTitle

This adds a function for querying the current title of a window.  This
currently returns a copy of the last title set via GLFW.

Fixes #1448
Closes #1909
Closes #2482

docs/news.md

@@ -41,6 +41,12 @@ to whatever window is behind it.  This can also be changed after window
 creation with the matching [window attribute](@ref GLFW_MOUSE_PASSTHROUGH_attrib).
 
 
+#### Ability to get a window's title {#features_34_get_window_title}
+
+GLFW now supports retrieving a window's title with the @ref glfwGetWindowTitle
+function.
+
+
 #### Wayland libdecor decorations {#wayland_libdecor_34}
 
 GLFW now supports improved fallback window decorations via
@@ -253,6 +259,7 @@ then GLFW will fail to initialize.
  - @ref glfwGetPlatform
  - @ref glfwPlatformSupported
  - @ref glfwInitVulkanLoader
+ - @ref glfwGetWindowTitle
 
 
 #### New types in version 3.4 {#types_34}

docs/window.md

@@ -919,6 +919,15 @@ If you are using C++11 or C11, you can use a UTF-8 string literal.
 glfwSetWindowTitle(window, u8"This is always a UTF-8 string");
 ```
 
+The window title can be retrieved with @ref glfwGetWindowTitle.
+
+```c
+const char* title = glfwGetWindowTitle(window);
+```
+
+The title returned is an internally managed copy of the title set
+by @ref glfwCreateWindow or @ref glfwSetWindowTitle. It does not
+include any additional text which may be appended by the platform.
 
 ### Window icon {#window_icon}