[gcc(refs/vendors/ibm/heads/perf)] doc: minor --enable-checking wording fixes

[gcc(refs/vendors/ibm/heads/perf)] doc: minor --enable-checking wording fixes

[Jiu Fu Guo]

https://gcc.gnu.org/g:8bc6d0a2da6134e4108703bde6e401efcf5ca544

commit 8bc6d0a2da6134e4108703bde6e401efcf5ca544
Author: Roman Zhuykov <zhroma@ispras.ru>
Date:   Tue Feb 25 14:08:00 2020 +0300

    doc: minor --enable-checking wording fixes
    
    gcc/ChangeLog:
             doc/install.texi (--enable-checking): Adjust wording.

Diff:
---
 gcc/ChangeLog        |  4 ++++
 gcc/doc/install.texi | 10 ++++++----
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index dba986dfdff..64120a91609 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2020-02-25  Roman Zhuykov  <zhroma@ispras.ru>
+
+	* doc/install.texi (--enable-checking): Adjust wording.
+
 2020-02-25  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/93868
diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index 09207ccf1da..9b24a06d961 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -1848,8 +1848,9 @@ properly if you are building the compiler with GCC@.
 
 When the option is not specified, the active set of checks depends on context.
 Namely, bootstrap stage 1 defaults to @samp{--enable-checking=yes}, builds
-from release archives default to @samp{--enable-checking=release}, and
-otherwise @samp{--enable-checking=yes,extra} is used.  When the option is
+from release branches or release archives default to
+@samp{--enable-checking=release}, and otherwise
+@samp{--enable-checking=yes,extra} is used.  When the option is
 specified without a @var{list}, the result is the same as
 @samp{--enable-checking=yes}.  Likewise, @samp{--disable-checking} is
 equivalent to @samp{--enable-checking=no}.
@@ -1872,8 +1873,9 @@ checking with extra checks that might affect code generation and should
 therefore not differ between stage1 and later stages in bootstrap.
 
 The @samp{valgrind} check requires the external @command{valgrind} simulator,
-available from @uref{http://valgrind.org/}.  The @samp{df}, @samp{rtl},
-@samp{gcac} and @samp{valgrind} checks are very expensive.
+available from @uref{http://valgrind.org/}.  The @samp{rtl} checks are
+expensive and the @samp{df}, @samp{gcac} and @samp{valgrind} checks are very
+expensive.
 
 @item --disable-stage1-checking
 @itemx --enable-stage1-checking