chore(AIP-217): fix AIP-159 link (#1559)

Author: aqelkp

aip/general/0217.md

@@ -186,7 +186,7 @@ If the `bool return_partial_success` field is set to `true` in a request that is
 scoped beyond the supported granualirty of the API's ability to reasonably
 report unreachable resources, the API **should** return an `INVALID_ARGUMENT`
 error with details explaining the issue. For example, if the API only supports
-`return_partial_success` when [Reading Across Collections][aip159], it returns
+`return_partial_success` when [Reading Across Collections][aip-159], it returns
 an `INVALID_ARGUMENT` error when given a request scoped to a specific parent
 resource collection. The supported granularity **must** be documented on the
 `return_partial_success` field.