Fix notation of time domain (#2110)

Co-authored-by: NikolaiFa <NikolaiFa@beckhoff.com>

Author: Tc-Fast

docs/2_1_common_math.adoc

@@ -15,7 +15,7 @@ The real part latexmath:[t_R] of this tuple is the <<independent>> variable of t
 During continuous-time integration the integer part of time latexmath:[t_I = 0].
 latexmath:[t_I] is a counter to enumerate (and therefore distinguish) the events at the same continuous-time instant latexmath:[t_R].
 This time definition is also called "super-dense time" in literature, see, for example, <<LZ07>>.
-An ordering is defined on latexmath:[\mathbb{\textsf{T}}] that leads to the notation in <<table-model-exchange-math-notation>>.
+An ordering is defined on latexmath:[\mathbb{T}] that leads to the notation in <<table-model-exchange-math-notation>>.
 
 .Conventions and notation used for time.
 [#table-model-exchange-math-notation]