Remove non-standard pow10 filter in favor of exp10 (#3059)

The pow10 function was a glibc extension removed in 2.27. Use exp10 filter instead.

docs/content/manual/manual.yml

@@ -3197,7 +3197,7 @@ sections:
       One-input C math functions: `acos` `acosh` `asin` `asinh` `atan`
       `atanh` `cbrt` `ceil` `cos` `cosh` `erf` `erfc` `exp` `exp10`
       `exp2` `expm1` `fabs` `floor` `gamma` `j0` `j1` `lgamma` `log`
-      `log10` `log1p` `log2` `logb` `nearbyint` `pow10` `rint` `round`
+      `log10` `log1p` `log2` `logb` `nearbyint` `rint` `round`
       `significand` `sin` `sinh` `sqrt` `tan` `tanh` `tgamma` `trunc`
       `y0` `y1`.