Updated runtime files

This is a collection of various PRs from github that all require a minor
patch number:

1) https://github.com/vim/vim/pull/12612

    Do not conflate dictionary key with end of block

2) https://github.com/vim/vim/pull/12729:

    When saving and restoring 'undolevels', the constructs `&undolevels` and
    `:set undolevels` are problematic.

    The construct `&undolevels` reads an unpredictable value; it will be the
    local option value (if one has been set), or the global option value
    (otherwise), making it unsuitable for saving a value for later
    restoration.

    Similarly, if a local option value has been set for 'undolevels',
    temporarily modifying the option via `:set undolevels` changes the local
    value as well as the global value, requiring extra work to restore both
    values.

    Saving and restoring the option value in one step via the construct
    `:let &undolevels = &undolevels` appears to make no changes to the
    'undolevels' option, but if a local option has been set to a different
    value than the global option, it has the unintended effect of changing
    the global 'undolevels' value to the local value.

    Update the documentation to explain these issues and recommend explicit
    use of global and local option values when saving and restoring.  Update
    some unit tests to use `g:undolevels`.

3) https://github.com/vim/vim/pull/12702:

    Problem:    Pip requirements files are not recognized.
    Solution:   Add a pattern to match pip requirements files.

4) https://github.com/vim/vim/pull/12688:

    Add indent file and tests for ABB Rapid

5) https://github.com/vim/vim/pull/12668:

    Use Lua 5.1 numeric escapes in tests and add to CI

    Only Lua 5.2+ and LuaJIT understand hexadecimal escapes in strings.  Lua
    5.1 only supports decimal escapes:

    > A character in a string can also be specified by its numerical value
    > using the escape sequence \ddd, where ddd is a sequence of up to three
    > decimal digits. (Note that if a numerical escape is to be followed by a
    > digit, it must be expressed using exactly three digits.) Strings in Lua
    > can contain any 8-bit value, including embedded zeros, which can be
    > specified as '\0'.

    To make sure this works with Lua 5.4 and Lua 5.1 change the Vim CI to
    run with Lua 5.1 as well as Lua 5.4

6) https://github.com/vim/vim/pull/12631:

    Add hurl filetype detection

7) https://github.com/vim/vim/pull/12573:

    Problem:   Files for haskell persistent library are not recognized
    Solution:  Add pattern persistentmodels for haskell persistent library

closes: #12612
closes: #12729
closes: #12702
closes: #12688
closes: #12668
closes: #12631
closes: #12573

Co-authored-by: lacygoill <lacygoill@lacygoill.me>
Co-authored-by: Michael Henry <drmikehenry@drmikehenry.com>
Co-authored-by: ObserverOfTime <chronobserver@disroot.org>
Co-authored-by: KnoP-01 <knosowski@graeffrobotics.de>
Co-authored-by: James McCoy <jamessan@jamessan.com>
Co-authored-by: Jacob Pfeifer <jacob@pfeifer.dev>
Co-authored-by: Borys Lykah <lykahb@fastmail.com>
diff --git a/runtime/doc/undo.txt b/runtime/doc/undo.txt
index cc33482..dc2274c 100644
--- a/runtime/doc/undo.txt
+++ b/runtime/doc/undo.txt
@@ -111,9 +111,19 @@
 parts.  E.g., for each sentence.  |i_CTRL-G_u|
 
 Setting the value of 'undolevels' also closes the undo block.  Even when the
-new value is equal to the old value.  In |Vim9| script: >
-	&undolevels = &undolevels
+new value is equal to the old value.  Use `g:undolevels` to explicitly read
+and write only the global value of 'undolevels'. In |Vim9| script: >
+	&g:undolevels = &g:undolevels
 In legacy script: >
+	let &g:undolevels = &g:undolevels
+
+Note that the similar-looking assignment `let &undolevels=&undolevels` does not
+preserve the global option value of 'undolevels' in the event that the local
+option has been set to a different value.  For example: >
+	" Start with different global and local values for 'undolevels'.
+	let &g:undolevels = 1000
+	let &l:undolevels = 2000
+	" This assignment changes the global option to 2000:
 	let &undolevels = &undolevels
 
 ==============================================================================
@@ -366,12 +376,20 @@
 When you set 'undolevels' to -1 the undo information is not immediately
 cleared, this happens at the next change.  To force clearing the undo
 information you can use these commands: >
-	:let old_undolevels = &undolevels
-	:set undolevels=-1
+	:let old_undolevels = &l:undolevels
+	:setlocal undolevels=-1
 	:exe "normal a \<BS>\<Esc>"
-	:let &undolevels = old_undolevels
+	:let &l:undolevels = old_undolevels
 	:unlet old_undolevels
 
+Note use of `&l:undolevels` to explicitly read the local value of 'undolevels'
+and the use of `:setlocal` to change only the local option (which takes
+precedence over the corresponding global option value).  Saving the option value
+via the use of `&undolevels` is unpredictable; it reads either the local value
+(if one has been set) or the global value (otherwise).  Also, if a local value
+has been set, changing the option via `:set undolevels` will change both the
+global and local values, requiring extra work to save and restore both values.
+
 Marks for the buffer ('a to 'z) are also saved and restored, together with the
 text.