Update slides.md: remove ! as a logical negation operator

f7693da1 · Damien François · 26fe0d55 · f7693da1
--- a/slides.md
+++ b/slides.md
@@ -348,7 +348,7 @@ Consists of one or more logical operators and logical, numeric or relational ope
 |     `.EQV.`     |     `==`     |     `A .EQV. B`      |  logical equivalence |
 |     `.NEQV.`    |     `/=`    |     `A .NEQV. B`      |  logical inequivalence |
 |     `.XOR.`     |     `/=`     |     `A .XOR. B`      |  exclusive `OR` (same as `.NEQV.`) |
-|     `.NOT.`     |     `!`     |     `.NOT. A`      |  logical negation |
+|     `.NOT.`     |             |     `.NOT. A`      |  logical negation |

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