Use a word boundary, current code was currently failing when parsing the definition of because it would also match `CooperativeMatrixOp` from a later mention of `SPIRV_KHR_CooperativeMatrixOperandsAttr`.
Use a word boundary, current code was currently failing when parsing the definition of because it would also match `CooperativeMatrixOp` from a later mention of `SPIRV_KHR_CooperativeMatrixOperandsAttr`.