Documentation: some improvements about the "decimal-point character".

* doc/README.dev: update about the use in the MPFR manual (mpfr.texi).
* doc/mpfr.texi: minor correction.

doc/README.dev

@@ -1193,9 +1193,10 @@ MPFR manual (mpfr.texi):
   * Use "decimal-point character" (as in ISO C) when the meaning is
     the corresponding character ("." or ",", depending on the locale),
     not "decimal point", "decimal separator", "fractional point", or
-    "radix point" (the latter is fine in certain contexts). This is
-    just the name of this character (as initially defined for base 10)
-    and does not imply a number written in decimal.
+    "radix point" (the latter is fine with a mathematical meaning).
+    This is just the name of this character (as originally defined
+    for base 10) and does not imply a number written in decimal.
+    Note: POSIX uses the term "radix character".
   * Use "@minus{}" for the minus character, not "-".
   * Warning! Texinfo is not like TeX. Whitespace is preserved in the
     info file. So, do not use additional space for .texi indentation.

doc/mpfr.texi

@@ -2895,8 +2895,8 @@ for @samp{a}, @samp{b}, @samp{e}, @samp{f}, and @samp{g} specifiers and
 
 The @code{mpfr_t} number is rounded to the given precision in the direction
 specified by the rounding mode (see below if the precision is missing).
-Similarly to the native C types, the precision is the number of digits
-output after the decimal point, except for the @samp{g} and @samp{G}
+Similarly to the native C types, the precision is the number of digits output
+after the decimal-point character, except for the @samp{g} and @samp{G}
 conversion specifiers, where it is the number of significant digits
 (but trailing zeros of the fractional part are not output by default),
 or 1 if the precision is zero.