Rename mj_stackAlloc to mj_stackAllocNum.

PiperOrigin-RevId: 561040193
Change-Id: I49ea21ffb5b596471d2aacefb1961c11c5c905d0

doc/APIreference/APIfunctions.rst

@@ -53,12 +53,12 @@ mjMARKSTACK
    #define mjMARKSTACK int _mark = d->pstack;
 
 This macro is helpful when using the MuJoCo stack in custom computations. It works together with the next macro and the
-:ref:`mj_stackAlloc` function, and assumes that mjData\* d is defined. The use pattern is this:
+:ref:`mj_stackAlloc` family of functions, and assumes that mjData\* d is defined. The use pattern is this:
 
 .. code-block:: C
 
    mjMARKSTACK;
-   mjtNum* temp = mj_stackAlloc(d, 100);
+   mjtNum* temp = mj_stackAllocNum(d, 100);
    // ... use temp as needed
    mjFREESTACK;