fix typos; added another test for rollback

base/changes.txt

@@ -9,7 +9,7 @@ not part of the distribution.
 2025-01-29  Frank Mittelbach  <[email protected]>
 
 	* ltoutput.dtx (subsubsection{Float control}):
-	When floats are to be placed an a test fails \@reqcolroom needs
+	When floats are to be placed and a test fails, \@reqcolroom needs
 	to be reset to the value prior to the failed test (gh/1645)}
 
 2025-01-23  Frank Mittelbach  <[email protected]>

base/doc/ltnews41.tex

@@ -491,21 +491,21 @@ \subsection{Make \cs{label}, \cs{index}, and \cs{glossary} truely invisible in r
 
 \subsection{Correct the float placement algorithm}
 
-When floats are placed onto the current or next page, \LaTeX{} makes
+When floats are added to the current or next page, \LaTeX{} makes
 several tests to find an area that can receive the float. One of these
 tests calculates how much space is already used on the page and how
-much additional space is necessary to place the float in a particular
-area. This means it looks at the height of the float, but also at the
+much additional space is needed to place the float in a particular
+area. This means that it looks not only at the height of the float but also at the
 values from \cs{intextsep} (for \texttt{h} floats) or
 \cs{textfloatsep} and \texttt{floatsep} (for \texttt{t} and \texttt{b}
 floats). The resulting space requirement is then stored in an internal
-variable and compared to thespace  still available on the page.
+variable and compared to the space still available on the page.
 
 If the test fails, the algorithm tries the next area. Unfortunately,
-it reused the value in that internal variable as the starting point
+it was reusing the value in that internal variable as the starting point
 for the next test without removing the added space for the float
 separation (\cs{intextsep}, \cs{floatsep}, or \cs{textfloatsep}). Thus
-the comparison was made with a wrong (i.e., to high) value and as a
+the comparison was being made with the wrong value (i.e., to high) and as a
 result the test may have incorrectly concluded that a float doesn't
 fit, even though in fact it did.
 

base/ltoutput.dtx

@@ -3008,7 +3008,7 @@
        \advance \@reqcolroom \ht\@currbox
 %    \end{macrocode}
 %    We save the current value of \cs{@reqcolroom} so that we can
-%    return to this value later, if a test fails that may have added
+%    return to this value later, in case a test fails that may have added
 %    something to it.
 %  \changes{v1.4n}{2025/01/29}{Save current value of \cs{@reqcolroom} (gh/1645)}
 %    \begin{macrocode}
@@ -4579,7 +4579,7 @@
 %
 %
 %  \begin{macro}{\saved@reqcolroom}
-%    Saved value of \cs{@reqcolroom}, neded when making several tests.
+%    Saved value of \cs{@reqcolroom}; this is needed when making several tests.
 %    \begin{macrocode}
 %</2ekernel>
 %<*2ekernel|latexrelease>
@@ -4841,8 +4841,8 @@
 %<latexrelease|fltrace>                 {\@flcheckspace}{float placement calculation}%
 \def \@flcheckspace #1#2{%
 %    \end{macrocode}
-%    When this test is executed the value of \cs{@reqcolroom} may be
-%    not longer correct due to a previous test that altered it. We
+%    When this test is executed, the value of \cs{@reqcolroom} may
+%    no longer be correct due to a previous test that altered it. We
 %    therefore reset it to a value saved earlier.
 %  \changes{v1.4n}{2025/01/29}{Reset current value of \cs{@reqcolroom} (gh/1645)}
 %    \begin{macrocode}