Suppress traceback chaining for tex subprocess failures.

For tex failures (e.g., `figtext(.5, .5, "\N{snowman}", usetex=True)`),
instead of
```
Traceback (most recent call last):
  File ".../matplotlib/texmanager.py", line 253, in _run_checked_subprocess
    report = subprocess.check_output(
  File "/usr/lib/python3.10/subprocess.py", line 420, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
  File "/usr/lib/python3.10/subprocess.py", line 524, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['latex', '-interaction=nonstopmode', '--halt-on-error', '../71cab2b5aca12ed5cad4a481b3b00e42.tex']' returned non-zero exit status 1.

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
    <a long traceback>
    raise RuntimeError(
RuntimeError: latex was not able to process the following string:
b'\\u2603'

Here is the full report generated by latex:
This is pdfTeX, Version 3.141592653-2.6-1.40.23 (TeX Live 2021) (preloaded format=latex)
<the tex output>
```

instead report the failure in a single block, as
```
Traceback (most recent call last):
    <a long traceback>
    raise RuntimeError(
RuntimeError: latex was not able to process the following string:
b'\\u2603'

Here is the full command invocation and its output:

latex -interaction=nonstopmode --halt-on-error ../71cab2b5aca12ed5cad4a481b3b00e42.tex

This is pdfTeX, Version 3.141592653-2.6-1.40.23 (TeX Live 2021) (preloaded format=latex)
<the tex output>
```
(the exception chaining is not particularly informative, and we can move
the only relevant info -- the command we tried to run -- to the second
exception).

Author: anntzer

lib/matplotlib/texmanager.py

@@ -261,11 +261,13 @@ def _run_checked_subprocess(cls, command, tex, *, cwd=None):
             raise RuntimeError(
                 '{prog} was not able to process the following string:\n'
                 '{tex!r}\n\n'
-                'Here is the full report generated by {prog}:\n'
+                'Here is the full command invocation and its output:\n\n'
+                '{format_command}\n\n'
                 '{exc}\n\n'.format(
                     prog=command[0],
+                    format_command=cbook._pformat_subprocess(command),
                     tex=tex.encode('unicode_escape'),
-                    exc=exc.output.decode('utf-8'))) from exc
+                    exc=exc.output.decode('utf-8'))) from None
         _log.debug(report)
         return report