* Mark module as modified if convert-to-half removes decorations.
If the convert-to-half pass does not change the body of the function,
but removes decorations, it returns that nothing changed. This is
incorrect, and will be fixed.
Fixes https://github.com/KhronosGroup/SPIRV-Tools/issues/4117
* Update comment for RemoveDecorationsFrom
The first pass applies the RelaxedPrecision decoration to all executable
instructions with float32 based type results. The second pass converts
all executable instructions with RelaxedPrecision result to the equivalent
float16 type, inserting converts where necessary.
