Doc fixes for grammar and typos (bug#23746)

Doc fixes for grammar and typos (bug#23746)

* doc/emacs/files.texi (Customize Save):
* doc/emacs/frames.texi (Window Dividers):
* doc/emacs/misc.texi (Printing):
* doc/lispref/compile.texi (Compiler Errors):
* doc/lispref/keymaps.texi (Changing Key Bindings):
* doc/lispref/loading.texi (Named Features):
* doc/lispref/markers.texi (Marker Insertion Types):
* doc/lispref/modes.texi (Mode Hooks):
* doc/lispref/text.texi (Undo):
* src/floatfns.c (Fldexp):
* src/xfaces.c (syms_of_xfaces):
Minor doc fixes for grammar and typos (bug#23746).