Disallow providing a stack of vectors to linalg.solve (#305)

* Disallow providing a stack of vectors

* Update copy

Co-authored-by: Leo Fang <[email protected]>

Co-authored-by: Leo Fang <[email protected]>

Author: kgryte

spec/extensions/linear_algebra_functions.md

@@ -484,7 +484,7 @@ Whether an array library explicitly checks whether an input array is full rank i
 
 -   **x2**: _<array>_
 
-    -   ordinate (or "dependent variable") array `B`. If `x2` has shape `(..., M)`, `x2` is equivalent to an array having shape `(..., M, 1)`, and `shape(x2)` must be compatible with `shape(x1)[:-1]` (see {ref}`broadcasting`). If `x2` has shape `(..., M, K)`, each column `k` defines a set of ordinate values for which to compute a solution, and `shape(x2)[:-1]` must be compatible with `shape(x1)[:-1]` (see {ref}`broadcasting`). Should have a floating-point data type.
+    -   ordinate (or "dependent variable") array `B`. If `x2` has shape `(M,)`, `x2` is equivalent to an array having shape `(..., M, 1)`. If `x2` has shape `(..., M, K)`, each column `k` defines a set of ordinate values for which to compute a solution, and `shape(x2)[:-1]` must be compatible with `shape(x1)[:-1]` (see {ref}`broadcasting`). Should have a floating-point data type.
 
 #### Returns