Update TeX.gitignore

When we use 'thmtools' package for creating 'List of Theorems', auxiliary file '.loe' is created, just as '.toc' for 'Table of Contents' and '.lof' for 'List of Figures'.

TeX.gitignore

@@ -141,6 +141,9 @@ sympy-plots-for-*.tex/
 *.pytxcode
 pythontex-files-*/
 
+# thmtools
+*.loe
+
 # TikZ & PGF
 *.dpth
 *.md5