Apparent misfire (wrong extension loaded) when generating GL_EXT_texture_filter_minmax
Short version: Requesting `EXT_texture_filter_minmax` gave me `EXT_raster_multisample` instead?

Long version:
I ran GLAD off the webservice. The comment block in glad.c was

```
/*

    OpenGL, OpenGL ES loader generated by glad 0.1.16a0 on Wed Jan 10 20:23:31 2018.

    Language/Generator: C/C++
    Specification: gl
    APIs: gl=3.3, gles2=3.0
    Profile: core
    Extensions:
        GL_ARB_texture_storage,
        GL_EXT_texture_compression_s3tc,
        GL_EXT_texture_filter_anisotropic,
        GL_EXT_texture_filter_minmax,
        GL_EXT_texture_sRGB,
        GL_OVR_multiview
    Loader: False
    Local files: False
    Omit khrplatform: False

    Commandline:
        --profile="core" --api="gl=3.3,gles2=3.0" --generator="c" --spec="gl" --no-loader --extensions="GL_ARB_texture_storage,GL_EXT_texture_compression_s3tc,GL_EXT_texture_filter_anisotropic,GL_EXT_texture_filter_minmax,GL_EXT_texture_sRGB,GL_OVR_multiview"
    Online:
        http://glad.dav1d.de/#profile=core&language=c&specification=gl&api=gl%3D3.3&api=gles2%3D3.0&extensions=GL_ARB_texture_storage&extensions=GL_EXT_texture_compression_s3tc&extensions=GL_EXT_texture_filter_anisotropic&extensions=GL_EXT_texture_filter_minmax&extensions=GL_EXT_texture_sRGB&extensions=GL_OVR_multiview
*/
```

The generated files replaced, in version control, a version of glad.c and glad.h produced by exactly the same arguments except no `GL_EXT_texture_filter_minmax`. The diff was as follows:
(This diff has been slightly hand edited for example I added some printfs.)

[addminmax.zip](https://github.com/Dav1dde/glad/files/1623941/addminmax.zip)
)

The following issues are seen:
1. By code inspection, the expected symbols for `GL_EXT_texture_filter_minmax`  are not generated by GLAD. The docs for the extension are [here](https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_texture_filter_minmax.txt). I expect `TEXTURE_REDUCTION_MODE_EXT` and `WEIGHTED_AVERAGE_EXT` symbols. These are not in the diff, however in the diff for GLAD I do find symbols such as `glRasterSamplesEXT`, `RASTER_SAMPLES_EXT` and MULTISAMPLE_RASTERIZATION_ALLOWED_EXT being defined AND LOADED IN `load_GL_EXT_texture_filter_minmax()`. In fact GLAD appears to be creating exactly those symbols used in `EXT_raster_multisample`, which I did not request (docs [here](https://developer.nvidia.com/sites/default/files/akamai/opengl/specs/GL_EXT_raster_multisample.txt)).
2. When the code is compiled, `GLAD_GL_EXT_texture_filter_minmax` is a true value, yet the code:
```
#define GL_TEXTURE_REDUCTION_MODE_EXT 0x9366
#define GL_WEIGHTED_AVERAGE_EXT 0x9367
glTexParameteri(canvas->texture.id, GL_TEXTURE_REDUCTION_MODE_EXT, result);
```
Results in the OpenGL error 1280 Invalid Enum being generated.

Conclusion: GLAD appears to be reading the wrong extension out of the spec and mislabeling it as `GL_EXT_texture_filter_minmax`.