doc: Periodic grammarcheck and spellcheck of documentation. * func.txi: Correct two misspellings * cumtrapz.m, dblquad.m, quadgk.m, quadl.m, quadv.m, trapz.m, triplequad.m, cond.m, gmres.m, bzip2.m, compare_versions.m, getappdata.m, unpack.m, ver.m, glpk.m, pkg.m, axis.m, uigetdir.m, uigetfile.m, view.m, prctile.m, quantile.m, unidcdf.m, unidinv.m, isstrprop.m, balance.cc, besselj.cc, cellfun.cc, colamd.cc, dot.cc, eigs.cc, fftw.cc, matrix_type.cc, pinv.cc, qr.cc, quad.cc, quadcc.cc, qz.cc, regexp.cc, schur.cc, time.cc (gmtime), typecast.cc urlwrite.cc bitfcns.cc (bitshift), data.cc (rem, norm, merge) debug.cc (dbstatus), dirfns.cc (glob), file-io.cc (freport), load-path.cc (genpath), load-save.cc (save), mappers.cc (islower, isupper, tolower, toupper) oct-hist.cc (edit_history), ov-fcn-inline.cc (vectorize), ov.cc (subsref), syscalls.cc (stat), variables.cc (whos, clear): Improve docstrings. Removed trailing whitespace characters on line.

--- a/src/data.cc
+++ b/src/data.cc
@@ -518,7 +518,7 @@
   "-*- texinfo -*-\n\
 @deftypefn  {Mapping Function} {} rem (@var{x}, @var{y})\n\
 @deftypefnx {Mapping Function} {} fmod (@var{x}, @var{y})\n\
-Return the remainder of the division @code{@var{x} / @var{y}}, computed \n\
+Return the remainder of the division @code{@var{x} / @var{y}}, computed\n\
 using the expression\n\
 \n\
 @example\n\
@@ -4748,7 +4748,7 @@
 Frobenius norm of @var{A}, @code{sqrt (sum (diag (@var{A}' * @var{A})))}.\n\
 \n\
 @item other @var{p}, @code{@var{p} > 1}\n\
-@cindex general p-norm \n\
+@cindex general p-norm\n\
 maximum @code{norm (A*x, p)} such that @code{norm (x, p) == 1}\n\
 @end table\n\
 \n\
@@ -6398,7 +6398,7 @@
 \n\
 In the array mask case, both @var{tval} and @var{fval} must be either\n\
 scalars or arrays with dimensions equal to @var{mask}.  The result is\n\
-constructed as follows: \n\
+constructed as follows:\n\
 \n\
 @example\n\
 @group\n\