DOC: fix formatting of a return value of polynomial fit methods

Fixes #19897

The 2nd return value of the following methods/functions were badly
formatted and the list was all appearing in a single line. Changed them
to separate points which are rendered nicely.
 - numpy.polyfit
 - numpy.ma.polyfit
 - numpy.polynomial.polynomial.polyfit
 - numpy.polynomial.polynomial.Polynomial.fit
 - numpy.polynomial.chebyshev.chebfit
 - numpy.polynomial.chebyshev.Chebyshev.fit
 - numpy.polynomial.hermite.hermfit
 - numpy.polynomial.hermite.Hermite.fit
 - numpy.polynomial.hermite_e.hermefit
 - numpy.polynomial.hermite_e.HermiteE.fit
 - numpy.polynomial.laguerre.lagfit
 - numpy.polynomial.laguerre.Laguerre.fit
 - numpy.polynomial.legendre.legfit
 - numpy.polynomial.legendre.Legendre.fit

Also fixed erroneous links to `numpy.full` which were actually referring
to the `full` argument. Changed those to code strings (double backticks)
from single backticks.

Also fixed formatting issues in the 3rd return value of numpy.polyfit
(and hence also numpy.ma.polyfit).

1 files changed, 5 insertions, 5 deletions

diff --git a/numpy/polynomial/_polybase.py b/numpy/polynomial/_polybase.py
index 5525b232b..8a72af278 100644
--- a/numpy/polynomial/_polybase.py
+++ b/numpy/polynomial/_polybase.py
@@ -958,12 +958,12 @@ class ABCPolyBase(abc.ABC):
             of interest, do ``new_series.convert().coef``.
 
         [resid, rank, sv, rcond] : list
-            These values are only returned if `full` = True
+            These values are only returned if ``full == True``
 
-            resid -- sum of squared residuals of the least squares fit
-            rank -- the numerical rank of the scaled Vandermonde matrix
-            sv -- singular values of the scaled Vandermonde matrix
-            rcond -- value of `rcond`.
+            - resid -- sum of squared residuals of the least squares fit
+            - rank -- the numerical rank of the scaled Vandermonde matrix
+            - sv -- singular values of the scaled Vandermonde matrix
+            - rcond -- value of `rcond`.
 
             For more details, see `linalg.lstsq`.