Add GDShader

[FireCatMagic]

Description

Adds support for GDShader / Godot Shading Language. Will close the issue I made for it: #7067
GDShader is the shading language used for Godot Engine https://godotengine.org/
It is very similar to GLSL https://docs.godotengine.org/en/stable/tutorials/shaders/shader_reference/shading_language.html

This language has been known by the community as both GDShader and Godot Shading Language, as it lacked a true name. This problem was solved and it is officially being known as GDShader. (see godotengine/godot-proposals#10784)

Checklist:

• I am adding a new language.
  • The new extension is used in hundreds of repositories on GitHub.com
    • Search results for each extension:
      • https://github.com/search?type=code&q=NOT+is%3Afork+path%3A*.gdshader+shader_type
      • https://github.com/search?type=code&q=NOT+is%3Afork+path%3A*.gdshaderinc
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s):
      • https://github.com/gdquest-demos/godot-shaders/blob/main/godot/Shaders/dissolve.gdshader
      • https://docs.godotengine.org/en/stable/tutorials/shaders/your_first_shader/your_first_3d_shader.html
      • https://github.com/gdquest-demos/godot-shaders/blob/main/godot/Shaders/gaussian_blur.gdshader
      • https://docs.godotengine.org/en/stable/tutorials/shaders/shader_reference/shader_preprocessor.html
      • https://godotshaders.com/shader/stylized-grass-with-wind-and-deformation/
      • https://godotshaders.com/shader/wind-waker-water-no-textures-needed/
    • Sample license(s):
      In same order of sources:
      • MIT
      • MIT
      • MIT
      • MIT
      • MIT
      • CC0
  • I have included a syntax highlighting grammar: [URL to grammar repo] https://github.com/GodOfAvacyn/gdshader-lsp.git
  • I have added a color
    • Hex value: #478CBF
    • Rationale: The color used for Godot's other language, GDScript, is #355570, so I didn't want to use an exact same color. I was thinking from the start to differentiate them I would still use a shade of Godot blue, but lighter. So I went and color-picked the Godot Engine logo and it was the perfect color - still a Godot color but enough to differentiate from GDScript files.
  • I have updated the heuristics to distinguish my language from others using the same extension.

[lildude]

We can't accept an unlicensed grammar. All grammars must have a licence and it must be one of these to be accepted:

linguist/vendor/licenses/config.yml

Lines 4 to 15 in 9b1023e

	- apache-2.0
	- bsd-2-clause
	- bsd-3-clause
	- cc0-1.0
	- isc
	- mit
	- mpl-2.0
	- ncsa
	- permissive
	- unlicense
	- wtfpl
	- zlib

[FireCatMagic]

Ok, I removed gdshader-lsp

https://github.com/godotengine/godot-vscode-plugin Also supports GDShader (and GDScript) and has the MIT license - but it seems like this grammar is already included in the project, so I can't add it