Reference page for GetTextureSubImage omits valid format enumerators

See here: https://registry.khronos.org/OpenGL-Refpages/gl4/html/glGetTextureSubImage.xhtml

The 4.5 spec says:
> GetTextureSubImage
> ...
> level, format, type and pixels have the same meaning as for GetTexImage.

Going there, we see:
> GetTexImage
> ...
> format is a pixel format from table 8.3

Table 8.3 has the formats from the above link to the reference page for `glGetTextureSubImage`, except it also has eight `_INTEGER` formats. These formats should be added to the reference page for the function.

Update: this issue also affects the reference page for `glReadPixels`: https://registry.khronos.org/OpenGL-Refpages/gl4/html/glReadPixels.xhtml

Compare the glGetTextureSubImage and glReadPixels reference pages linked in the issue with the OpenGL 4.5 specification's Table 8.3. Update the reference-page sources so the eight missing _INTEGER format enumerators are listed, then verify both generated pages contain them.

Written by the indexing model from the issue text.